During the brief passage through the city Tarzan came to the conclusion that the black inhabitants were the servants, perhaps slaves; the brown men, the soldiers and shopkeepers, while the whites formed the aristocratic or patrician class. Well within the city the company turned to the left into another broad avenue and shortly afterward approached a great circular edifice constructed of hewn granite blocks. Arched apertures flanked by graceful columns rose tier upon tier to a height of forty or fifty feet, and above the first story all of these arches were open. Through them Tarzan could see that the enclosure was without a roof and he guessed that this lofty wall enclosed an arena, since it bore a marked resemblance to the Colosseum at Rome. As they came opposite the building the head of the column turned and entered it beneath a low, wide arch and here they were led through numerous corridors in the first story of the building and down a flight of granite steps into gloomy, subterranean chambers, where, opening from a long corridor, the ends of which were lost in darkness in both directions, were a series of narrow doorways before which swung heavy iron gates. In parties of four or five the prisoners were unchained and ordered into the dungeons that lay behind. Tarzan found himself with Lukedi and two other Bagegos in a small room constructed entirely of granite blocks. The only openings were the narrow, grated doorway, through which they entered, and a small, grated window in the top of the wall opposite the door, and through this window came a little light and air. The grating was closed upon them, the heavy padlock snapped, and they were left alone to wonder what fate lay in store for them. _Chapter Eight_ Mallius Lepus conducted von Harben from the quarters of the captain of the gate in the south wall of the island city of Castrum Mare and, summoning a soldier, bade him fetch Gabula. "You shall come with me as my guest, Erich von Harben," announced Mallius Lepus, "and, by Jupiter, unless I am mistaken, Septimus Favonius will thank me for bringing such a find. His dinners lag for want of novelty, for long since has he exhausted all the possibilities of Castrum Mare. He has even had a black chief from the Western forest as his guest of honor, and once he invited the aristocracy of Castrum Mare to meet a great ape. "His friends will be mad to meet a barbarian chief from Germania--you are a chief, are you not?" and as von Harben was about to reply, Mallius Lepus stayed him with a gesture. "Never mind! You shall be introduced as a chief and if I do not know any different I cannot be accused of falsifying." Von Harben smiled as he realized how alike was human nature the world over and in all periods of time. "Here is your slave now," said Mallius. "As the guest of Septimus Favonius you will have others to do your bidding, but doubtless you will want to have your own body-servant as well."