“There’s a lot of foolish talk,” he continued, after a few minutes’ pause, “about some race of fossil monsters having continued to the present time, as though, at almost any time, one might happen to come across an Agathosaurus at sea, or a Tyrannosaurus on land. There are, of course, a few survivals, such as the shrimp-like Nebalia, which goes back to the Cambrian Period, to the very beginning of life, but all these survivals are small and inconspicuous. And Agathosaurus of the Cretaceous Period certainly wasn’t inconspicuous!” “Just how big was the Agathosaurus?” queried the boy. “Big enough to satisfy any sea-serpent-hunter,” was the reply. “The Agathosaurus had a neck thirty feet long and a body as large as that of a small elephant, with powerful limbs turned into swimming paddles. This long neck, with its small head and sharp-toothed jaws, must have worked havoc with the fish of the Jurassic seas.” [Illustration: _Courtesy of American Museum of Natural History._ THE FIERCEST MONSTER THAT EVER LIVED. Tyrannosaurus, the tyrant saurian, greatest of flesh-eating giants, about to attack a family of Triceratops, “they of the three-horned face.”] “Weren’t there any fish big enough to give him a fight?” “H’m, hardly,” the scientist replied meditatively. “Still, there was the Portheus Molossus, of course.” “The what?” asked the boy. “I haven’t ever heard of him.” “The bulldog fish,” his uncle explained. “Oh, Portheus was able to give a good account of himself. He had a head a little larger than that of a grizzly bear, with jaws even deeper than a bear’s in proportion to their length. The teeth stood about three inches above the gums, tiger-like, but, of course, they were fish teeth, much more slender and a great deal sharper. He had two rows of teeth which crossed each other, and even an Agathosaurus would have had trouble shaking off a Portheus if the fish took a fast hold on his snaky neck.” “I wish I could see a scrap like that now,” exclaimed Perry regretfully. “You were born about three million years too late,” was the reply, “for it’s fully as long ago since the saurians left. They were the strangest army, Perry, that ever trod the earth, some of them monsters of ferocity and terrible to look on, such as the Tyrannosaurus, which, as you can see, means the Tyrant Saurian, but most of them were slow, lumbering, and inoffensive. Of true quickness and agility they had none. “Over earth and air and sea, they were the masters. In the shallow seas they ruled with an iron hand; they filled great shells like turtles with a bulk vaster than has been seen since; they reared themselves on towering hind limbs like colossal kangaroos, their monstrous tails swinging free behind them; they donned fantastic armor, with spikes and horns, and living saws upon their backs, such as outdid the wildest imaginations of man; they even rose into the air and filled it with the flying dragons, as though to make fairy tales believable.