One additional note on Teredinidae - because many of the species bore in wood, it is rather difficult to say just where on the planet they are "native" to. They can be carried for hundreds or even thousands of miles in driftwood, and end up on beaches almost anywhere. Some species were long ago distributed worldwide, not only via driftwood, but especially in the hulls of wooden ships, before the days of metal hulls and anti-fouling paints. Their distribution to far northern and southern regions is restricted by water temperature (they like warmer water), but the same species are widely distributed throughout tropical, sub-tropical, and even temperate zones, circumglobal. Paul M.