Naming of moons underworld, and Nix (a respelling of Nyx), mother of Charon, is the goddess of darkness and the night. Kerberos is a giant three-headed dog who guards the entrance to the underworld. The fifth moon is named for the river Styx that forms the boundary between the worlds of the living and the dead. The name of Eris's moon Dysnomia was suggested by its discoverer Michael E. Brown, who also suggested the name of the dwarf planet. The name has two meanings: in mythology Dysnomia (lawlessness) is the daughter of Eris (chaos). However, the name is also an intentional reference to
The Dog in the Manger the grain, but who nevertheless prevented the horse from being able to eat anything either." The story was first glossed in the 1st century CE lexicon of Diogenianus as "The dog in the manger, concerning those who neither themselves use nor allow others to use: Insofar as the dog neither itself eats the barleycorns, nor allows the horse to". It was twice used in the following century by Greek writer Lucian: in "Remarks addressed to an illiterate book-fancier" and in his play "Timon the Misanthrope". One other contemporary poetic source is a paederastic epigram by Straton of Sardis in the