He pointed to a trough-like depression in the room. A curious arrangement. Probably for purposes of sanitation. Liquid ammonia, or something akin, entered the trough from a gushing tube set low in one wall, transversed the room, and exited through a second circular duct. These were the only openings in the chamber, save for—Tim glanced up, noticed several round holes. He studied these curiously. Lane answered his unspoken query.
"Yes, that's right. Ventilation. These devils may be inhuman in form but they're clever. They've built this underground city, equipped it with heat, light, ventilated it to maintain circulation—"
There was something wrong there. Tim frowned.
"Ventilation? Yet you say that stream is ammoniated enough to kill a man. Then how do they live?"
"They're not men," replied Lane bitterly. "They're vampires. Heaven knows how they can breathe this atmosphere, but they can. The ingenious, murdering..."
He didn't complete the sentence. For at that instant there came the scrape of movement outside their dungeon door. The door swung open. A bat-man entered. His hooked claw signalled them to come forth. Tim glanced at the older man. Lane shrugged resignedly.
"There's nothing else to do. Maybe we can strike a bargain with them. Our freedom for something they want."
But there was no hope in his voice. Tim threw an arm about Dorothy's shoulders. They followed their guide out of the room. There a cordon of other bat-creatures circled them, and Tim, for the first time, got an opportunity to see his captors at close range.
They weren't much to look at. They were such stuff as nightmares are made of. Tall, angular, covered from head to toe with a stiff, glossy pelt of fur. Their faces were lean and hard and predatory; their teeth sharp and protruding. Their wings were definitely chiropteric; the wing-membranes spanned from their shoulders to their claws, falling loosely away when not in use, and were anchored to stiff, horny knobs at clavicle and heel.