CRAB Lice, a troublesome kind of vermin, which stick so fast with their claws to the skin as to render it difficult to dislodge them. They are called placitula, morpiones, petole, and peffolata: they usually infest the arm pits and padenda. Cleanliness is the best preventative. But these vermin may be easily removed with the application of a little mercurial ointment.