From the explanatory blurb:
"The Carnival Playing card Deck was designed by Harry D. Wallace and originally published in 1925 by the Carnival Playing Card Co., New Orleans.
"The court cards are artistic and each of the four suits rpresents a different Mardi Gras figure. Spades are Proteus, a sea god who has the power to change his form at will. Hearts represent Comus, the god of festivity. Clubs are Momus, the god of mockery. Diamonds are Rex, the king of the Mardi Gras."