If you will look closely at the photograph, you will notice, within the head, and below the eye-socket, a row of recurved teeth. These are the teeth on the pterygoid bones, which are located on either side of the roof of the mouth, near the gullet, and are provided with twelve teeth, more or less. The lower jaw with its powerful sweep on its fulcrum, pressed the living prey firmly upon these teeth so that it could not come forward and escape. Then notice the ball-and-socket joint just back of the tooth-bearing bone or dentary, of the lower jaw. After the wriggling, struggling prey had been fastened on the teeth in the roof of the mouth, the mandibles were shortened by a spreading of this central joint, and the victim was forcibly pushed down the throat.
The species Clidastes velox of these Kansas mosasaurs, was, as its name indicates, very agile, with beautiful bones of so firm a texture that they have suffered less than any of the other fossil vertebrates from the vast pressure to which they have been subjected, not only from the enormous amount of material that has been heaped above them, but from the still more powerful upward push which has raised their burial-place three thousand feet above sea level.
I sent one very beautiful specimen of Clidastes to Vassar College; so complete, in fact, that it can be made into a panel mount.
I think no artist has more fully appreciated what these great reptiles must have been when alive than Mr. Sidney Prentice, now of the Carnegie Museum, whose beautiful restoration, made to illustrate Dr. Williston’s work on Kansas Mosasaurs, is here reproduced (Fig. [11]b). I am under obligations to him for the labor of his pencil. He has certainly put life into this denizen of the old Cretaceous ocean, and I do not believe that anyone, after a careful study of the skeleton, could find any fault with the restoration, from a scientific standpoint.
In this connection, I should like also to call attention to the beautifully preserved skull I sent to the Carnegie Museum. This specimen shows a complete side view of the head, with mandibles and maxilla, the teeth interlacing as perfectly as in life. The sclerotic plates that protect the eyeball are also in natural position.
The luxuriant life of the Cretaceous ocean was certainly remarkable. Fish swarmed everywhere, and often, as the specimens are uncovered, the scales are picked up by the wind, crumbled into dust, and scattered in every direction.
Among the most common of the fossil bones in those early days were those of a huge fish, whose vertebræ, with fragments of heads and jaws, were found in great abundance, although no perfect specimen has been discovered. Professor Cope, who described this fish, called it Portheus molossus. I secured a fine specimen on Robinson’s ranch, in Logan County. It lay in a small exposure of chalk along a grassy hill slope, within a stone’s throw of the ranch buildings. My son George was my assistant then, and we got out this specimen in the month of November. Our boarding place was five miles away, and every night the ground froze hard. Nothing daunted, we went to work with a will.
The head and trunk region had already been uncovered, and many of the ribs and spines had been swept away and lost. We took up the head and front fins in a great slab of plaster, as the chalk in which they lay had disintegrated under the influence of the frost. A violent windstorm was raging at the time, and to complete the slab, George had to bring water from a tank a hundred yards away. I can still see that boy running up with his pail of water, trying to carry it so that it would not be emptied by the raging, howling wind that was almost tearing his coat from his back, while I stood and shouted, “Hurry up! The plaster’s hardening!”
The rest of the column, to the tail, we took up separately, and as the great tail-fins and many of the caudal vertebræ were present with their spines, embedded in solid chalk, we removed five feet of superincumbent rock, cut a trench around the slab containing the bones, and took it up by digging under it.
This made another huge mass to be handled. The section containing the head weighed over six hundred pounds, and this tail section almost as much. The latter froze solid before we could get it up to the tent, where we kept a fire burning to dry out the water from the bones and thus prevent the injurious effects of freezing. I should like just here to express my gratitude to those ranchmen who gave their time and strength to assist me in handling these huge sections.