The saurischians were a diverse group of dinosaurs, with both carnivores and herbivores. They exhibited two-legged and four-legged means of propulsion. The carnivores included the large two-legged Allosaurus, Ceratosaurus, Tarbosaurus, and Tyrannosaurus. There were smaller, two-legged carnivores, too, such as Ornithomimus and the Dromaeosaurus, which had specialized feet and their unique, slashing, raptorial claws. The herbivorous saurischians that are best known are the large, four-legged sauropods, the largest dinosaurs to have walked Earth. These dinosaurs had long necks and tails, with relatively tiny heads. Included in this group are Brachiosaurus, Camarasaurus, Diplodocus, Mamenchisaurus, and Seismosaurus.