[1] For the well-known myth according to which Hermes made the first kithara out of a tortoise's shell and gave it to Apollo as compensation for stolen cattle, see the Homeric Hymn to Hermes 24 ff. (web address 1). For the noun xe/lus in other poetry see: Sappho fr. 118 L.-P.; Euripides, Alcestis 447 (web address 2), with the corresponding scholia); Callimachus, Hymn to Apollo 16, and passim in the Greek Anthology. Compare the lexicographical entries of the word in Hesychius, ps.-Zonaras, and the Etymologicum Magnum; also Hesychius s.vv. xe/lion, xe/lun e)/n t’ a)lu/rois, xelu/nh. For the kithara cf. alpha 4073, beta 110, theta 475, kappa 1590, kappa 1591, kappa 1650, nu 473, nu 478, phi 603, psi 17; see also Hesychius s.vv. au)lo/s, ba/rbitos, ki/qaris, kinu/ra, lu/ra, na/bla, fo/rmic, xeleu/s and ya/ltigc (all glossed as synonymous of kithara).
[2] cf. chi 190.
[3] Besides chi 190, the rare adjective o)strako/nwtos is also used in reference to snails (Athenaeus, Deipnosophists 10.455E = 10.83 Kaibel).