marine snail, Cantharidus opalus (Martyn, 1784)

The opal top shell has the distinction of being the first New Zealand animal to be scientifically recorded and illustrated. It was one of the species collected and taken back to Europe by members of the Endeavour expedition. Although formally named in 1784 by the English naturalist Thomas Martyn in The Universal Conchologist, the species had already been described and illustrated by the German naturalist J. E. Walch in the journal 'Der Naturforscher' (1774). Cantharidus opalus is endemic to the New Zealand region, occurring on rocky ground off Three Kings, North, South, Stewart, Chatham, and Snares Islands. It lives and feeds on algae between low tide and about 27 metres depth.