With the speed of the hunted, Hero Giles bounded forward, taking three and four steps at a stride, his jade green cloak snapping out behind. Down, ever downwards over the endless flight of stairs the aviators followed him until, spent and panting, the hard pressed five plunged down a final circular staircase and so gained a courtyard where waited a detachment of armored lancers whose yellow plumes and pennons shone bright in the glare of the flame suns. Staring anxiously upwards, the troopers nevertheless stood to attention in an orderly rank beside those curious Atlantean mounts called podokos. During all his sojourn in Atlans, Nelson had never become used to the hideous and awe-inspiring podokos which closely resembled the allosauri but were only eighteen feet long. Like the other monsters, they had tremendously developed hind legs which promised the speed now so vital for escape and safety. Ready in the tooth-studded jaws of each podoko was fitted a bronze bit together with a bridle and reins; and cinched up on each creature's back was one of those curious Atlantean saddles, which was built up at the cantle to overcome the downward slope of the podokos' spines. Need for vital haste was but too obvious and, as he drew near, Hero Giles gasped the command to be off. "Quick," he shouted, his scarred visage flushed and sweat-bathed. "Saddles! Speed! Speed! Cling fast as your beasts arise!" * * * * * All five literally hurled themselves into gorgeously caparisoned saddles. Instantly, the urging squatting podokos leaped to their feet. It was the work of a moment for Nelson to wrench his reptile around, for already Alden and the Atlantean cavalrymen were speeding across the wide paved court, their lance pennons fluttering bravely in the orange-hued glare. At top speed the rescuers dashed for a great, oval gateway while the podokos increased their gait; like aero-planes gathering speed, the faster the weird creatures traveled, the higher arose their tails. Then, following the frightened, backward glances of the hard-riding, red-haired lancers, Nelson suddenly discovered a new and terrible cause for this headlong flight, for, issuing from an unbarred gateway, came perhaps a dozen of _the terrible and enormous allosauri_, which, spying the fleeing cavalry, instantly gave chase. With a sense of despair, the aviators heard the ferocious bellows booming from behind and watched the appallingly swift progress of those uncouth monsters as, leaping high into the air, the allosauri covered between fifty and sixty feet at a single bound.