7 .-- Skulls of Dinosaurs, illustrating the principal types--_Anchisaurus_ after Marsh, the others from American Museum specimens.] II.

_Amphibious Dinosaurs_ or _Sauropoda_.

With blunt-pointed teeth and blunt claws, quadrupedal, with elephant-like limbs and feet, long neck and small head.Unarmored.Principal dinosaurs of this group in America are _Brontosaurus_, _Diplodocus_, _Camarasaurus_ (_Morosaurus_) and _Brachiosaurus_, all of the Upper Jurassic and Comanchic periods.
III.

_Beaked Dinosaurs_ or _Predentates_.

With a horny beak on the front of the jaw, cutting or grinding teeth behind it.