Ornithischia

Ornithischia ( /ɔrnɨˈθɪskiə/ or-ni-THISS-kee-ə) or Predentata is an extinct order of beaked, herbivorous dinosaurs. The name ornithischia is derived from the Greek ornitheos (ορνιθειος) meaning 'of a bird' and ischion (ισχιον) meaning 'hip joint'. They are known as the 'bird-hipped' dinosaurs because of their bird-like hip structure, even though birds actually belong to the 'lizard-hipped' dinosaurs (the saurischians). Being herbivores that sometimes lived in herds, they were more numerous than the saurischians. Many were prey animals for the theropods and were usually smaller than the sauropods.