Occurs around New Zealand with probably an identical species in Chile. Shell made of two valves, one lightly convex or flat and one cupped. Widespread around New Zealand from lower shore to 60m but commercial quantities only in Foveaux Strait and Tasman Bay. Most abundant in Foveaux Strait in depths of 20-48 metres. Not cultivated. Taken by dredging. Catch restricted to a season, 1 March to 31 August, and an annual quota currently set at 115,000 sacks (70-80 dozen per sack).