from The Century Dictionary.
- noun A mussel-shell of the stone-boring genus Lithodomus (or Lithophagus), of the family Mytilidæ, as the Mediterranean L. dactylus, abounding in the subaqueous columns of the temple of Serapis at Pozzuoli, near Naples: so called from its shape or appearance. See
Sorry, no etymologies found.
The one called the date-shell can, assisted by its liquid acid, pierce the hardest stone with its cylindrical gimlet.