Notes Various species are shown, there are over 6000, more than 1000 in N.Z.! They can range from tiny crusts or lentil-shaped colonies to large, tree-like shapes. Bryozoans produce remarkable chemicals and are currently being used in cancer research. Not only do they live on reefs, but some deep reefs (like those just off the Otago Peninsula) are built of bryozoans! Oamaru limestone is made primarily of bryzoan skeletons. "