What is an instrument of music, as a lyre, -- the first lyre having been made, it is said, by drawing strings over a tortoise shell. When Jubal struck the chorded shell. Dryden called?

shell — An instrument of music, as a lyre, -- the first lyre having been made, it is said, by drawing strings over a tortoise shell. When Jubal struck the chorded shell. Dryden. (Webster's 1913.)