These organisms have auricles projecting from each side of the head, each adorned with long cilia. Their foot is segmented, with relatively short toes, and they possess a retrocerebral sac. Their trophi are typically asymmetrical, with roughly hemispherical rami and a cervical eyespot. They typically measure between 100 to 1,000 µm in total length, often exceeding 300 µm. Some species are covered by a gelatinous secretion, and many are found in littoral habitats, with some being particularly common and impressive. The uncus, a plate-like structure, usually features one or two principal teeth along with small accessory teeth in some cases. Most species previously classified under Copeus are now considered part of the Notommata genus. These organisms have an unadorned body, a distinct neck, and a head with an oblique anterior surface. Their trophi are rod-shaped (virgate) and asymmetric, and their foot is two-jointed with short toes.