Erected by Simonetti, by order of Pius VI. In the centre is a magnificent vase of red porphyry, 46 feet in circumference, found in the House of Nero. The large mosaic represents combats between Centaurs and Lapithæ, and nymphs carried on the backs of monsters; in the centre, under the vase, is the head of Medusa. The border represents the adventures of Ulysses, Neptune, and monsters. The principal statues are 537, 538, Tragedy and Comedy; 539, Bust of Jupiter; 540, Colossal statue of Antinoüs; 546, Statue of Ceres; 545, Bust of Antinoüs; 544, Hercules, in gilt bronze, found in 1864 during the restoration of the foundations of the Biscioni Palace, which occupies the site of the Theatre of Pompey, in the middle of which stood the Temple of Venus Victrix, which this statue adorned; 542, Colossal Juno; 547, Bust of Ocean; 548, Nerva, a seated statue crowned with bronze oak wreath; 550, The Emperor Claudius; 552, Juno; 553, The Genius of Augustus. _We now pass into_ THE HALL OF THE MUSES. It contains statues of muses, busts of Greek philosophers, poets, and statesmen, all of which deserve special attention. _Left._ 525, Bust of Pericles; 524, Seated Statue of Sappho; 523, Bust of Aspasia. _Right._ 535, Mnemosyne, the mother of the muses; 511, Erato, muse of love song; 514, Bust of Socrates; 515, Calliope, muse of epic poetry; 516, Apollo, as leader of the muses; 517, Terpsichore, muse of dancing; 520, Euterpe, muse of melody. _Left._ 508, Polyhymnia, muse of sacred poetry; 505, Clio, muse of history; 506, Bust of Demosthenes; 504, Urania, muse of astronomy; 503, Thalia, comic and pastoral muse; 499, Melpomene, muse of tragedy. _Beyond, left._ 492, Sophocles; 491, Silenus; 490, Diogenes. _Right._ 498, Epicurus; 496, Homer. _Now pass into_ THE HALL OF THE ANIMALS. The principal objects of interest are--124, Mithraic Sacrifice found at Ostia, in the temple dedicated to the worship of the Persian deity; 139, Commodus on Horseback; 143, Sleeping Shepherd; 228, Triton carrying off a Nereid. _We next enter_ THE GALLERY OF STATUES. In the centre of the gallery is a magnificent bath of the finest Oriental alabaster. _Right-hand side on entering._ 248, Clodius Albinus, governor of Britain under Commodus; 250, Cupid, by Praxiteles, the "Genius of the Vatican;" 255, Paris; 259, Minerva as the Peace-bearer; 261, Penelope; 262, Caligula; 264, Apollo with the Lizard; 267, Drunken Faun; 270, Urania; 271, Posidippus, the master of Greek comedy. _Entrance to Hall of Busts_ (_see below_). 390, Menander; 391, Nero as Apollo; 392, Septimius Severus; 393, Dido; 394, Neptune; 396, Narcissus; 398, Macrinus; 399, Æsculapius and Hygeia; 401, Fragment of Hæmon and Antigone; 402, Seneca; 405, One of the fifty daughters of Danaus drawing water from Lethe; 406, Faun, repetition of Praxiteles. _Entrance on left to Cabinet of Masks._ 414, Sleeping Ariadne; 417, Mercury, by Ingenui; 420, Lucius Verus. THE HALL OF BUSTS.