The Greek Gods, by Evslin, Evslin, & Hoopes.
This happy fellow had the misfortune to be an excellent musician - a realm Apollo considered his own - and where he would brook no rivalry. Hearing the satyr praised too often, Apollo invited him to a contest. The winner was to choose a penalty to which the loser would have to submit, and the Muses were to judge. So Marsyas played his flute and Apollo played his lyre. They played exquisitely; the Muses could not choose between them. Then Apollo shouted, "Now you must turn your instrument upside down, and play and sing at the same time. That is the rule. I go first." Thereupon the god turned his lyre upside down, and played and sand a hymn praising the gods, and especially their beautiful daughters, the Muses. But you cannot play a flute upside down, and certainly cannot sing while playing it, so Marsyas was declared the loser. Apollo collected his prize. He flayed Marsyas alive, and nailed his skin to a tree. A stream gushed from the tree's roots and became a river. People called the river Marsyas, and that is still its name.