Ornithischia (or-nith-IS-kee-ah) is one of the two orders of dinosaurs
(Saurischia being the other). The division is based on the shape of the
pelvic bone shape.
The ornithischian pubis and ischium both point backward. (The saurischian
pubis juts forward, and its ischium points backward.)
The ornithischians were all herbivorous, and they included some of the
most interesting-looking dinosaurs. Ornithischian dinosaurs include three
suborders: Ornithopoda, Marginocephalia and Thyreophora.