The subclass Dinosauria, as known to-day, I have divided into three orders: the Theropoda, or carnivorous forms; the Sauropoda, or herbivorous quadrupedal forms; and the Predentata, also herbivorous, and including several suborders, namely, the Stegosauria and Ceratopsia, both quadrupedal, and the Ornithopoda, containing bipedal bird-like reptiles.