Mourka, an extraordinary alley cat is one of famed choreographer George Balanchine's prize pupils. He has learned to do entre-chats, pas de chats and even a grand jete. When photographer Martha Swope caught Mourka doing one of his spectacular leaps, Life magazine printed the memorable photo and Mourka's reputation was made instantly for millions of Americans. Here, Miss Swope's pictures and former Ballerina Tanaquil Le Clercq's text convey his many exploits and suggest that Mourka may well be the most accomplished feline in the world.