(Amphidesma subtriangulatum).

A shellfish abundant at about half tide on coastal sandy beaches of the northern half of the North Island, it is white and solid, from 1 ½ to 3 in. in length, and can be distinguished from the common pipi by the position of the apex of the shell which is not central. It resembles the toheroa in shape, but is smaller and more solid, and the valves fit tightly all round. In the toheroa the shell gapes slightly at each end. Tuatua has an excellent flavour, but is rather sweeter than the toheroa.

by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.