These Dinosaurs came in sizes and differed considerably as to looks and eating and getting about. Some were as small as cats, some walked on four legs, some--like the gentleman at lunch--walked on two. Some were strict vegetarians, while others would have nothing but meat. The Big Boys of the whole tribe were called the Sauropoda or reptile-footed Dinosaurs. One of these, whose bones were found in Colorado, was sixty-five feet long when complete, and he must have weighed around twenty tons. His family nickname was Diplodocus or "Double Beam," because of his long, beam-like neck and his long, beam-like tail. GENTLE MR. DIPLODOCUS AND HIS WAYS Considering the reputation some of the other Dinosaurs had as bad citizens, it is only fair to the Diplodocus to say that he was really a gentle creature, and never disturbed anybody--unless somebody disturbed him first. Then he would give them a switch with that tail of his, and it was a switching they were not likely to forget. But his great delight--indeed, his main occupation in life--was to sit deep in the water, prop himself up with his great long tail, like a kangaroo, with just his head out, like a turtle in a pond. Then he would strain little water bugs and similar things through his teeth. He got his meals in this way, very much as the whales do now. And elephants! You ought to have seen some of the members of the elephant family that arrived after the reptile age, the mammoths, for instance. These huge creatures and many other strange animals were all over the place. It was just like a circus day everywhere all the time. Such elephants don't travel with circuses now, of course, because they were all killed during that dreadful winter, but you can see them in museums, all dressed in their skeletons and neatly held together with wires. [Illustration: _From the mural painting by Charles R. Knight in the American Museum of Natural History_ WHEN ELEPHANTS WORE UNDERCLOTHES This painting on the walls of the American Museum of Natural History in New York City shows herds of reindeer and mammoths in the Ice Age. They didn't mind the cold as elephants do to-day, because of their woolly underclothes. They fed on the shoots and cones of those firs and pines. The reindeer, then as now, ate the lichens we call "reindeer moss," first scraping away the snow with their feet. ] HOW THE MAMMOTHS PASSED AWAY