The body of these organisms is typically divided into three main regions: the head, trunk, and foot. They usually possess a well-developed corona that is divided into two parts and located on a retractable head. Some distinctive features include well-developed foot glands, a mouth opening connected to a long esophagus, strong teeth (often categorized by a tooth index), and numerous cilia. Their digestive and reproductive systems are situated within the trunk region of their bodies, with the stomach being the most prominent organ. In certain genera, spherical pellets can be found within the stomach, which are later expelled as feces.