any of various marine snails of the subclass Prosobranchia (class Gastropoda) that constitute the genus Haliotis and family Haliotidae. The characteristic planispiral shell has a broad, oblique aperture, which gives it an earlike shape, and a series of perforations through the shell involved in directing water flow. The inside of the shell is always nacreous, often in iridescent greens and blues. The snails live attached to rocks by a large adherent foot. They feed on algae and are found in the shallow waters of rocky shores worldwide. The larger species are called ormer in England, abalone in the United States, paua in New Zealand, and awabi in Japan. Several of these larger species are found on the western coast of North America and include the red, green, black, and pink abalones (Haliotis rufescens, H. fulgens, H. cracherodi, and H. corrugata, respectively). Overexploitation has reduced stocks in many parts of the world; there are catch limits and even total protection in some areas. Several species are commercially cultivated in hatcheries, particularly on the west coast of the United States and along China's east coast. The shells of Haliotis have been extensively used for ornamental and decorative purposes from early times.