Acontiaria possessing a strong mesogloeal sphincter. Mesenteries not differentiated into macrocnemes and microcnemes; usually only the first six or 12 pairs are perfect, the first six usually sterile. Nematocysts of acontia are b-mastigophores only.
These anemones typically occur offshore, often in deep water. The column is usually thick and tough, cartilaginous or leathery in texture, and often bears solid mesogloeal tubercles and periderm. In many species the ectoderm is thin and often becomes rubbed away, exposing the mesogloea, which gives a characteristic satiny sheen to the external appearance. Many hormathiids prefer to attach to organic substrates, living or dead; this tendency is carried further in the well-known anemone/hermit-crab relationships involving the genera Calliactis and Adamsia.