Iguanodon

Iguanodon, a genus of Dinosauria (q.v.) belonging to the subdivision Ornithopoda (bird-footed), which have been found in the Upper Jurassic and Lower Cretaceous rocks of south-east England and Belgium. They rivalled the elephant in size, being upwards of 30 feet long and having a thigh-bone as much as 5 feet in length. Their front limbs were much smaller than the hind ones, and these latter show marked affinities to those of the ostrich-like birds. Their feet were three-toed, and, judging from their footprints, they seem to have walked almost entirely on their hind legs. There was a long and massive tail, adapting the animal for sitting up, as do those of the kangaroo, the megatherium (q.v.), or the woodpeckers. The teeth resemble those of the iguana of the present day, being in distinct sockets, curved, leaf-shaped, and serrated along the margin; but they are ground down above like the grinders of mammals, and were succeeded by others from below. The front of the jaws was toothless and beak-like. Iguanodon was very imperfectly known until the recent discovery of twenty-four extremely perfect specimens at Bernissart in Belgium, in detached pockets of Wealden strata. Several of these are now mounted in the Brussels Museum. They were undoubtedly purely herbivorous animals.