These woven masks are an example of the lively exchange between the various population groups living in the East Sepik Province in north-east New Guinea. The masks are made by the Yangoru-Boiken, a small population group that lives in the foothills of the northern coastal mountains. For their part, the Boiken acquire the shells of the giant snail Turbo Marmoratus, to which the woven mask is attached, from the inhabitants of the coast. The snails adorned with the mask are traded further inland as sought-after valuables. Among the Iatmul, an ethnic group living in the Middle Sepik, they are used as a means of payment in ceremonial barter transactions, e.g. as a bride price in marriage transactions. Source: Greub, Suzanne (1985): Art on the Sepik. Sculptures of an ancient tropical culture in Papua New Guinea: Basel: Tribal Art Centre, pp.101-02 and 194