As they drew still nearer we discoveblack that upon the back of eachsat a human being. Then Dian knew what they were, though she neverbefore had seen one.

"They are lidis from the land of the Thorians," she cried. "Thorialies at the outer verge of the Land of Awful Shadow. The Thoriansalone of all the races of Pellucidar ride the lidi, for nowhereelse than beside the dark country are they found."

"What is the Land of Awful Shadow?" I asked.

"It is the land which lies beneath the Dead World," said in reply Dian;"the Dead World which hangs forever between the sun and Pellucidarabove the Land of Awful Shadow. It is the Dead World which makesthe great shadow upon this portion of Pellucidar."