members of the cryptic brachiopod-coralline sponge community in the Caribbean (Jamaica, Curasao), Red Sea and Pacific. High densities are found on the undersides of foliaceous corals or overhangs and in the interiors of crevices or caves (6). A variety of rarer forms are known from depths of between 500 m and 6000 m (3). Examples are the relict species Sphenarina ezogremena and Septicollarina hemichinata known only from single specimens collected at a depth of 2W m in the Bali Sea (27). Probably the richest brachiopod area in the northern hemisphere are in Puget Sound, around the San Juan Islands (Washington State, U.S.A) and off the southern coast of British Columbia, Canada (30). Brachiopods are rarely found washed up on the sea shore since the shell breaks easily once the animal dies (2). In the inarticulate brachiopods the Lingulidae and Discinidae occur in tropical and subtropical regions. The two genera in the family Lingulidae are geographically disjunct: Lingula is found in shallow inshore waters in the east Atlantic and Indo-west Pacific regions, while Glottidia is confined to both coasts of the Americas. Representatives of the Discinidae are restricted to shelf waters in all oceans, except for a single cosmopolitan deep-sea species. The Craniidae occur worldwide, but mainly in temperate shelf waters. All groups may be exceedingly abundant, and can be found at densities of up to 1000 per m (17,18). Most articulate brachiopods live permanently attached to hard material on the sea floor either by a fleshy stalk or by cementing the ventral valve directly to the surface, but a few species are able to attach to aggregated sediment grains and other soft substrates (9,31). They feed mainly on plankton and other organic material collected by the filaments on the lophophore, which create a current of water through the mantle cavity; they may also feed directly on dissolved nutrients (2,5). They are not found in areas of soft, fine sediment with a high rate of sedimention, since such conditions would clog the lophophore, but they can survive strong water currents. They do not generally tolerate salinities deviating more than a few per cent from that of normal sea water (2). Sexes are normally separate although there are a few hermaphroditic species. Eggs and sperm are usually shed into the water, where fertilization occurs, but a few warm-water species brood their eggs. The fertilized egg develops into a free-swimming larva which, after a short planktonic existence, sinks to the bottom and develops into the adult form (5). In the Inarticulata, lingulids live in semi-permanent vertical burrows in sandy sediments (19). They occur in areas that may be subjected to lowered salinities for relatively prolonged periods. Craniids require a hard substratum for attachment, as do the discinids, which are often found in clumps attached to each other. Little is known of the salinity tolerance of these two families. Larval development patterns appear to enhance wide dispersal of lingulids and discinids (lf15) but crinoids have a short larval life and only limited potential for dispersal (20). SCIENTIFIC INTEREST AND POTENTIAL VALUE The phylum is particularly important in the study of evolutionary history, as brachiopod remains are often abundant in fossil-bearing rocks of almost every geological age. Brachiopods have one of the longest observable evolutionary histories, having existed for at least 550 million years (2); the continuity of their fossil record is extremely good (9). The genus Lingula is the classic 'living fossil, remaining unaltered in external appearance and probably in life habit for about 500 million years. It is the most studied of all brachiopod genera. Lingula has been utilized as a food item in Japan (26), the Philippines, Burma, Thailand and by Australian aborigines. Some discinids have been recorded as fouling ships' hulls (12), but they are likely to be of only minor significance in this regard. No other species of commercial importance is known. 534