Dinosaurs, with Special Reference to the American Museum Collections

by William Diller Matthew

Fig. 22.—Restoration of Brontosaurus by C.R. Knight, under direction of Professor Osborn.

"The contrast between the massive structure of the limb-bones, ribs and tail, and the light construction of the backbone, neck and skull, suggests that the animal was amphibious, living chiefly in shallow water, where it could wade about on the bottom, feeding upon the abundant vegetation of the coastal swamps and marshes, and pretty much out of reach of the powerful and active Carnivorous Dinosaurs which were its principal enemies. The water would buoy up the massive body and prevent its weight from pressing too heavily on the imperfect joints of the limb and foot bones, which were covered during life with thick cartilage, like the joints of whales, sea-lizards and other aquatic animals. If the full weight of the animal came on these imperfect joints the cartilage would yield and the ends of the bones would grind against each other, thus preventing the limb from moving without tearing the joint to pieces. The massive, solid limb and foot bones weighted the limbs while immersed in water, and served the same purpose as the lead in a diver's shoes, enabling the Brontosaurus to walk about firmly and securely under water. On the other hand, the joints of the neck and back are exceptionally broad, well fitting and covered with a much thinner surface of cartilage. The pressure was thus much better distributed over the joint, and the full weight of the part of the animal above water (reduced as it was by the cellular construction of the bones) might be borne on these joints without the cartilage giving way.

"Looking at the mounted skeleton we may see that if a line be drawn from the hip joint to the shoulder-blade, all the bones below this are massive, all above (including neck and head) are lightly constructed. This line may be taken to indicate the average water-line, so to speak, of this Leviathan of the Shallows. The long neck would enable the animal, however, to wade to a considerable depth, and it might forage for food either in the branches or the tops of trees, or more probably, among the soft succulent water-plants of the bottom. The row of short spoon-shaped stubby teeth around the front of the mouth would serve to bite or pull off soft leaves and water-plants, but the animal evidently could not masticate its food, and must have swallowed it without chewing as do modern reptiles and birds.

"The brain-case occupies only a small part of the back of the skull, so that the brain must have been small even for a reptile, and its organization (as inferred from the form of the brain-case) indicates a very low grade of intelligence. Much larger than the brain proper was the spinal cord, especially in the region of the sacrum, controlling most of the reflex and involuntary actions of the huge organism. Hence we can best regard the Brontosaurus as a great, slow-moving animal automaton, a vast storehouse of organized matter directed chiefly or solely by instinct, and to a very limited degree, if at all, by conscious intelligence. Its huge size and its imperfect organization, compared with the great quadrupeds of today, rendered its movements slow and clumsy; its small and low brain shows that it must have been automatic, instinctive and unintelligent."

Composition of the Brontosaurus Skeleton. "The principal specimen, No. 460, is from the Nine Mile Crossing of the Little Medicine Bow River, Wyoming. It consists of the 5th, 6th, and 8th to 13th cervical vertebrae, 1st to 9th dorsal and 3rd to 19th caudal vertebrae, all the ribs, both coracoids, parts of sacrum and ilia, both ischia and pubes, left femur and astragalus, and part of left fibula. The backbone and most of the neck of this specimen were found articulated together in the quarry, the ribs of one side in position, the remainder of the bones scattered around them, and some of the tail bones weathered out on the surface.

"From No. 222, found at Como Bluffs, Wyo., were supplied the right scapula, 10th dorsal vertebra, and right femur and tibia.

"No. 339, from Bone-Cabin Quarry, Wyoming, supplied the 20th to 40th caudal vertebrae, No. 592, from the same locality the metatarsals of the right hind foot; and a few toe bones are supplied from other specimens.

Fig. 23.—Skull of Diplodocus from Bone-Cabin Quarry, north of Medicine Bow, Wyoming.

"The remainder of the skeleton is modelled in plaster, the scapula, humerus, radius and ulna from the skeleton in the Yale Museum, the rest principally from specimens in our own collections. The modelling of the skull is based partly upon specimens in the Yale Museum, but principally upon the complete skull of Morosaurus shown in another case.