But we have not yet mentioned the greatest wonder of fossil animals; this is the _Iguanodon_, whose bones have been found in England. It was a sort of lizard, and its thigh bones were eight inches in diameter. This creature must have been from seventy to a hundred feet long, and one of its thighs must have been as large as the body of an ox. I have given a portrait of this monster, drawn by Mr. Billings, an excellent young artist, whom you will find at No. 10, Court st., Boston. I cannot say that the picture is a very exact likeness; for as the fellow has been dead some thousands of years, we can only be expected to give a family resemblance. We have good reason to believe, however, that it is a tolerably faithful representation, for it is partly copied from a design by the celebrated John Martin, in London, and to be found in a famous book on the wonders of geology, by Mr. Mantel. There was another curious animal, called the _Pterodactyle_, with gigantic wings. The skull of this animal must have been very large in proportion to the size of the skeleton, the jaws themselves being almost as large as its body. [Illustration: _Skeleton of the Pterodactyle._] They were furnished with sharp, hooked teeth. The orbits of the eyes were very large; hence it is probable that it was a nocturnal animal, like the bat, which, at first sight, it very much resembles in the wings, and other particulars. The word pterodactyle signifies wing-fingered; and, if you observe, you will find that it had a hand of three fingers at the bend of each of its wings, by which, probably, it hung to the branches of trees. Its food seems to have been large dragon-flies, beetles and other insects, the remains of some of which have been found close to the skeleton of the animal. The largest of the pterodactyles were of the size of a raven. One of them is pictured in the cut with the Iguanodon. Another very curious animal which has been discovered is the _Dinotherium_, being of the enormous length of eighteen feet. It was an herbiferous animal, and inhabited fresh water lakes and rivers, feeding on weeds, aquatic roots, and vegetables. Its lower jaws measured four feet in length, and are terminated by two large tusks, _curving downwards_, like those of the upper jaw of the walrus; by which it appears to have hooked itself to the banks of rivers as it slept in the water. It resembled the tapirs of South America. There appear to have been several kinds of the dinotherium, some not larger than a dog. One of these small ones is represented in the picture with the Iguanodon. The bones of the creatures we have been describing, were all found in England, France, and Germany, except those of the megatherium, which was found in South America. In the United States, the bones of an animal twice as big as an elephant, called the _Mastodon_, or _Mammoth_, have been dug up in various places, and a nearly perfect skeleton is to be seen at Peale’s Museum, in Philadelphia.