Another, called the Winged-lizard, had bat-like wings and dreadful jaws armed with numerous teeth. All these "Saurians" are believed to have frequented the sea or rivers; but another called the Great-lizard, was a land-animal, as was the Forest-lizard, and a monster kind of Toad with very curiously formed teeth. But no description will give you an idea of the size of these creatures, though I may tell you that a party of gentlemen dined inside the body of one great extinct lizard at the Crystal Palace, where models, not very accurately made, of the most remarkable ancient animals are to be seen. I think my first thought when I see the actual remains of these old-world monsters, with their terrible jaws, is that of thankfulness that they have passed away from sea and land. But we know that God who created them "saw that it was good," and in the Book of Job we may read His description of mighty and terrible creatures which show forth His power. We were speaking of a monster toad whose fossil remains have been found; and I must tell you that before we had done with the "Creeping Things," I was asked a difficult question. "To what class do the frogs and toads and newts belong? Are they Vertebrate animals? Do they belong to the land or the water?" I said they certainly do belong to the great Backboned family, and are placed in a class by themselves, as they are neither Mammalia, Birds, Fishes, nor Reptiles, properly speaking, and are called Amphibia, because they live, as it were, a double life. [Illustration: BROWN FROGS.] They have gills, which enable them to breathe in water, to begin with, and lungs which enable them to breathe in air, later on. They are mostly without scales, and do not need to drink, because they imbibe moisture from the air through their soft damp skin. When you see a frog hopping across your path, you see a creature which has known many a change in its life, for frogs are among those very interesting animals which undergo what are called _metamorphoses_. We have met with this word before, and may remember that it is used to express the change from one form to another which is wrought in some living creatures in the course of their growth. I daresay you imagine as I once did, that all young animals are like their parents, only on a smaller scale; for you see that a young horse, or elephant, or whale, a pup or a kitten, is at its birth in all respects just what it will be when full-grown, only smaller. So it is with the reptiles and the birds--the young ones, when hatched, are like the parents. But in the case of frogs and newts, and also most insects, the young ones do not merely increase in size as they grow, but pass from one stage of growth to another, each different from the former, until like the butterfly when it emerges from the chrysalis, they reach what is called their perfect state--and these metamorphoses or changes are very curious and interesting indeed.