n. A great carnivorous dinosaur from the Upper Cretaceous (Laramie) of North America, characterized by its small fore limbs, greatly elongated hind limbs inclosing large hollow cavities, and huge serrated teeth of which thirteen are present in the upper jaw and twelve or thirteen in the dentary. This dinosaur walked erect, as a biped, supporting the weight of the body on the hind limbs and tail.