1. (noun) nesting mussel, banded mussel, Modiolarca impacta - bivalve mollusc with a brown shell, frequently with a mixture of green near the edge. The centre is smooth, but both ends are ornamented with fine radiating ridges. The interior is highly iridescent. Found in both Islands, in seaweed or grass and under rocks, both in harbours and on ocean beaches. Also written as one word (i.e. kukumautoka) or three words (i.e. kuku mau toka).