(Neothais scalaris).

This is a solid, white, spirally ridged shell, up to 3 in. in height, common on intertidal rocks. The Maori name is hopetea. The egg cases of this shellfish are deposited in masses in caverns and on the under sides of boulders. They are crowded together, honeycomb fashion, are of cream to lilac colour, and each has a pinhole at the top from which the larval shell eventually emerges. This larva is an efficient free swimmer – hence the wide distribution of the species, which extends to Australia and Tasmania as well.

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