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Page:Popular Science Monthly Volume 24.djvu/368

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THE POPULAR SCIENCE MONTHLY.

fessor Dupont, director of the museum, and again shown to be those of the iguanodon.

For the past two years the bones have been under the steady investigation of M. L. Dollo, a former pupil of Professor Giard, of Lille, who has published four papers giving accounts of his observations, and is expected, when he gets through with his work, to publish an exhaustive treatise on the subject. He thinks he has the skeletons, or parts of them, of twenty-three individuals, two of which belong to Mantell's species (Iguanodon Mantelli), and twenty-one to the species Iguanodon Bernissartensis. One of the specimens has been restored and mounted by M. Depauw, and set up in a glass chamber in the court of the museum. It is nearly complete, only a few phalanges and other minor details being wanting, while, on account of the impossibility of detaching the bones, most of them have been mounted still joined to one another, and fastened to the matrix as they were taken from the mine. The figure has, of course, for this reason a little stiffness, but not enough to attract the attention of the merely casual observer, and stands, in the natural attitude of progression of the animal on land, erect on its hind-limbs, with the top of its snout fourteen feet two inches from the ground, and covering, from the tip of the tail to a point immediately under the tip of the snout, a length of twenty-three feet nine inches.

The iguanodon belongs to the sub-class of dinosaurians and the order Ornithopoda, or bird-footed. Among the special characteristics of the family of the iguanodons are a single row of teeth, three functional digits on the foot, and two symmetrical sternal plates. The last, which Professor Marsh, from his studies of specimens in the British Museum, regarded as clavicles, and traced in them a point of structural resemblance with birds, are declared by M. Dollo, from specimens at Bernissart, in which they are preserved in their natural relations, to be sternal, while no clavicles are found. There are, however, says Mr. H. N. Moseley, in "Nature," abundance of other points in the skeleton of the iguanodon "in which the remarkable resemblances between the Ornithopoda and birds indicated by Professor Huxley, more than twelve years ago, are borne out in a most remarkable manner. . . . First of all, there seems to be little doubt possible that the iguanodons walked, as he pointed out, on their hind-limbs erect, like birds, in somewhat the attitude of the accompanying figure (see Fig. 4). Several different lines of coincidence, as M. Dollo points out, tend to prove this. Firstly, the remarkable resemblances between the structure of the pelvis and the posterior limbs of birds, and the corresponding parts in the iguanodons. The points of resemblance of the ilium and ischium, pointed out by Professor Huxley, are fully confirmed by the Bernissart specimens. . . . The actual pubis is very large in the iguanodon, as will be seen in the figure, and projects forward and outward, forming an obtuse angle with the post--