I wonder if "The Carnival of the Animals" and "Danse Macabre" are the same piece? Why are they named differently?
The 12th movement of the suite "The Carnival of the Animals", Fossils, is copied partly from the "Danse Macabre", a piece previously written by Saint-Saëns.
It quotes the theme of Dance Macabre in a humorous way, and also several other tunes including "Au Clair de la Lune" and "Ah! Vous d'irai-je, Maman" (the tune English-speakers know as "Twinkle, Twinkle, Little Star" or "The ABC Song").