Naval fights held sometimes in Circus Maximus, 50; —must have been in canals of Colosseum, as Heliogabalus filled them with wine, 51; —called Circensian games, _ib._; —Martial distinguishes them, _ib._ Nero, substructures part of the time of, 1, 12; —gymnasium and naumachia of, on site of this amphitheatre, 5; —remains of aqueducts and piscina, _ib._; —gymnasium of, on the arena, 6; —brickwork of time of, _ib._; —supper of, in the amphitheatre, 7; —exterior of brick unfinished by him, and finished by Flavian Emperors in stone, 11; —two small chambers of brick, of his time, enclosed in travertine walls, 15; —awning of, mentioned by Pliny, 23; —amphitheatre of, not in Campus Martius, 56; —his Stagna were canals of aqueducts, 8. Netting to protect lower gallery of gold (or gilt) wire, called _retia_, 50. NISMES, amphitheatre still has a wooden floor with trap-doors in it, 46; arrangements below quite different, _ib._ Palaces, several made out of amphitheatre, 29. Passage, great, found at S.E. end, 34. Passages, small special, for messengers, intermediate between the great ones at Pozzuoli, and in Colosseum at Rome, 47; —central, or gulf, in all the amphitheatres, _ib._ Pavement, original here, 21 ft. below level of arena, 35. Pegmata, cages for wild beasts, 15; —described by Seneca, 16; —not only cages, but wooden machines, 49. Piers of travertine, introduced to support floors, 12; —from top to bottom, to carry upper gallery, 39. Piscinæ, remains of two, 11. Pit for a man to descend to feed the animals, 17. Plan, general, is oval, with galleries, vomitoria, &c., 18. Pliny mentions Scaurus and his _insane_ works, 56. Podium protected by wire netting and bars, 16. POLA, IN ISTRIA, Amphitheatre at, 45, 46; —built of white stone, _ib._; —two tiers of arches remain, _ib._; —A curious stone parapet, with indications of awning, _ib._; —Built against rocky mountain, _ib._; —Substructures in lower part, _ib._; —Canal for water visible, _ib._; —Square towers (for musicians?), 46. POZZUOLI (Puteoli), Arena of brick full of trap-doors, 13, 42; —Surface there flooded for _naumachia_, 13; —An intermediate passage for messengers, 47; —Building much smaller than those of Rome and Capua, 42; —Substructures more perfect and more highly finished, _ib._; —Arena of brick, with apertures for trap-doors, _ib._; —Arrangement for fixing masts for awning, as in Rome, 43; —Building also of time of Hadrian, _ib._; —Vaults preserved and used, _ib._ Rhodope, mountain of, represented as a scene here, 4.