Chelys means tortoise, and the instrument is the lyre whose soundbox is imagined as a shell. The Homeric Hymn to Hermes tells the origin as a piece of mischief: the newborn god finds a tortoise, empties it, stretches hide and arms and strings, and plays. He later gives the lyre to Apollo, which is one way the Greeks explained how a trickster’s gadget became the god’s civilised instrument.
The number of strings is not a single fact. Seven is the number schoolbooks like, and many classical images agree, but earlier and later lyres do not all obey. What stays stable is the kind of instrument: plucked, light enough to hold, associated with song, education, and Apollo, as against the aulos and its professional players.
A catalogue photograph should show the shell or the wooden body that stands in for it, the arms, the yoke, and the strings. Until that photograph is made, the green frame is a plug, not a reconstruction.
Recording
A recording belongs here. Add an audio URL on the instrument, and the player will take this slot.