Fig. 21.—Excavating the Brontosaurus skeleton. The upper photograph shows the anterior ribs of one side still lying in position. The backbone is being prepared for removal, the sections each containing three vertebrae, partly cased in plaster and burlap (see chapter XI.) The lower photograph shows a later stage of progress, the blocks being undercut and nearly ready to turn over and incase the under side. Strips of wood have been pasted into each section to strengthen it.
"It will appear, therefore, that the collection, preparation and mounting of this gigantic fossil has been a task of extraordinary difficulty. No museum has ever before attempted to mount so large a fossil skeleton, and the great weight and fragile character of the bones made it necessary to devise especial methods to give each bone a rigid and complete support as otherwise it would soon break in pieces from its own weight. The proper articulating of the bones and posing of the limbs were equally difficult problems, for the Amphibious Dinosaurs, to which this animal belongs, disappeared from the earth long before the dawn of the Age of Mammals, and their nearest relatives, the living lizards, crocodiles, etc., are so remote from them in either proportions or habits that they are unsatisfactory guides in determining how the bones were articulated and are of but little use in posing the limbs and other parts of the body in positions that they must have taken during life. Nor among the higher animals of modern times is there one which has any analogy in appearance or habits of life to those which we have been obliged by the study of the skeleton to ascribe to the Brontosaurus.
"As far as the backbone and ribs were concerned, the articulating surfaces of the bones were a sufficient guide to enable us to pose this part of the skeleton properly. The limb joints, however, are so imperfect that we could not in this way make sure of having the bones in a correct position. The following method, therefore, was adopted.
"A dissection and thorough study was made by the writer, with the assistance of Mr. Granger, of the limbs of alligators and other reptiles, and the position, size and action of the principal muscles were carefully worked out. Then the corresponding bones of the Brontosaurus were studied, and the position and size of the corresponding muscles were worked out, so far as they could be recognized from the scars and processes preserved on the bone. The Brontosaurus limbs were then provisionally articulated and posed, and the position and size of each muscle were represented by a broad strip of paper extending from its origin to its insertion. The action and play of the muscles on the limb of the Brontosaurus could then be studied, and the bones adjusted until a proper and mechanically correct pose was reached. The limbs were then permanently mounted in these poses, and the skeleton as it stands is believed to represent, as nearly as study of the fossil enables us to know, a characteristic position that the animal actually assumed during life....
"In proportions and appearance the Brontosaurus was quite unlike any living animal. It had a long thick tail like the lizards and crocodiles, a long, flexible neck like an ostrich, a thick short, slab-sided body and straight, massive, post-like limbs suggesting the elephant, and a remarkably small head for the size of the beast. The ribs, limb-bones and tail-bones are exceptionally solid and heavy; the vertebrae of the back and neck, and the skull, on the contrary are constructed so as to combine the minimum of weight with the large surface necessary for the attachment of the huge muscles, the largest possible articulating surfaces, and the necessary strength at all points of strain. For this purpose they are constructed with an elaborate system of braces and buttresses of thin bony plates connecting the broad articulating surfaces and muscular attachments, all the bone between these thin plates being hollowed into a complicated system of air-cavities. This remarkable structure can be best seen in the unmounted skeleton of Camarasaurus, another Amphibious Dinosaur." (The scientific name Camarasaurus=chambered lizard, has reference to this peculiarity of construction.)
"The teeth of the Brontosaurus indicate that it was an herbivorous animal, feeding on soft vegetable food. Three opinions as to the habitat of Amphibious Dinosaurs have been held by scientific authorities. The first, advocated by Professor Owen, who described the first specimens found sixty years ago (1841-60) and supported especially by Professor Cope, has been most generally adopted. This regards the animals as spending their lives entirely in shallow water, partly immersed, wading about on the bottom, or perhaps occasionally swimming, but unable to emerge entirely upon dry land.[12] More recently, Professor Osborn has advocated the view that they resorted occasionally to the land for egg laying or other purposes, and still more recently the view has been taken by Mr. Riggs and the late Professor Hatcher that they were chiefly terrestrial animals. The writer inclines to the view of Owen and Cope, whose unequalled knowledge of comparative anatomy renders their opinion on this doubtful question especially authoritative.
After Osborn