(Hyridella menziesi).
These bivalve shellfish are found in freshwater lakes, streams, and rivers. They grow to 4 in. in length and are always coated with a thick, greenish-brown horny epidermis. They have an interesting juvenile stage in which the larval shellfish spends its early life attached to the body or fins of a freshwater fish. This is the kakahi of the Maoris, formerly much favoured by them as a special food for young children and the sick.
by Arthur William Baden Powell, Assistant Director, Auckland Institute and Museum.