The Parasaurians

For a select few, it offered a dangerous vacation from the too-safe world of the 22nd century—a chance to hunt fantastically real robot analogs of the giant dinosaurs who ruled the Earth in mindless grandeur for a million centuries... Ross Fletcher could afford Megahunt's price—and welcomed the challenge and peril of hunting the "parasaurians." But the safari suddenly changed character, with Fletcher and his companions becoming the quarry, pursued by a hunter more deadly than any monster from the past—man.