1911 Encyclopædia Britannica (1911)
“ The separation of the Ratitae from the other birds, and their seemingly fundamental differences, notably the absence of the keel and of the power of flight, induced certain authors to go so far as to derive the Ratitae from the Dinosaurian reptiles, whilst Arrhaeopteryx (q.'v.) and the Carinatae were supposed to have sprung from some Pterosaurian or similar reptilian stock. Such vagaries require no refutation. But it is quite another question, whether the “ Ratitae ” form a natural group. ”
