Dinosaurs, with Special Reference to the American Museum Collections

by William Diller Matthew

Fig. 6.—Outline Restorations of Dinosaurs. Scale about nineteen feet to the inch.

These various kinds of Dinosaurs are customarily grouped as follows:

I. Carnivorous Dinosaurs or Theropoda. With sharp pointed teeth, sharp claws; bipedal, with bird-like hind feet, generally three-toed;[3] the fore-limbs adapted for grasping or tearing, but not for support of the body. The head is large, neck of moderate length, body unarmored. The principal Dinosaurs of this group in America are

Allosaurus, Ornitholestes—Upper Jurassic period.

Tyrannosaurus, Deinodon, Albertosaurus, Ornithomimus—Upper Cretacic period.

Fig. 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. All herbivorous, with pelvis of peculiar type, with hoofs instead of claws, and many genera heavily armored. Mostly three short toes on the hind foot, four or five on the fore foot. This group comprises animals of very different proportions as follows: