Why is a certain worm called the pierce-stone ?

Because it bores passages in rocks, even in the hardest marble, in the steins of coral, oyster-shells, the bottoms of ships, etc. and excavates a habitation at the termination of the passage. - Blumenbach.

The Lithophagus is another of these stone-boring animals, and an instance of its depredations on the hardest marble is shown by the celebrated, but mysterious, phenomenon, of the three large columns of Cippolino antico, in the temple of Serapis, at Pozzuolo, which, though at an elevation of twenty-seven feet above the level of the Mediterranean near them, are perforated in a circular manner by these animals.