In the last two years of his life, the Sicilian aristocrat Giuseppe Tomasi di Lampedusa, in addition to his internationally celebrated novel, The Leopard, also composed three shorter pieces of fiction that confirm and expand our picture of his brilliant late-blooming talent.   In the parable-like “Joy and the Law,” a mediocre clerk in receipt of an unexpected supplement to his Christmas bonus (an awkwardly outsize version of the traditional panettone) finds his visions of domestic bliss upset by unwritten rules of honor and obligation. At the heart of the collection stands “The Siren” and its redoubtable hero, Professor La Ciura, the only Hellenist scholar to claim firsthand experience of ancient Greek—from the mouth of the beautiful half-human sea creature he loved in his youth. The volume closes with the last piece of writing completed by the author, “The Blind Kittens,” a story originally conceived as the first chapter of a follow-up to The Leopard, a novel that would have traced the post-unification emergence of a new agrarian ruling class in Sicily, coarser than its predecessor but equally blind to the inexorable march of change.   This elegant new translation of Lampedusa’s complete short fiction, the first by a single hand, updates and corrects previously available English versions.