had the habit of a hippopotamus. The femur, or thigh-bone, in a large individual, was about thirty-three inches long, and the humerus nineteen inches. The teeth were flat, and had a serrated cutting edge like the teeth of the iguana; and hence the name, signifying iguana-like teeth; many of them, from old animals, are worn off short." Le Conte's "Geology" also says that "the animal takes its name from the form of its teeth, which are much like those of the iguana, a living herbivorous reptile, although in other respects there is little affinity." Figs. 1 and 2 show respectively the tooth of an iguanodon, and a section of the jaw of the iguana, for comparison.
Le Conte adds: "But the difference in size between the living and the extinct reptile is enormous. The iguana is from four to six feet long; the iguanodon was certainly thirty feet, perhaps fifty or sixty feet long, and of bulk several times greater than that of an elephant. A thigh-bone has been found fifty-six inches long, twenty-two inches in circumference at the shaft, and forty-two inches at the condyle. Its habits are supposed to have been something like those of a hippopotamus. Like this animal, it wallowed in the mud, and fed on the rank herbage of marshy grounds." The article "Iguanodon," in the "American Cyclopædia," in the course of its technical description of the bones of the animal that had been identified, suggests that the