We have in Kansas three genera of these mosasaurs as the celebrated Frenchman, Cuvier, named them in 1808. The word literally means a reptile of the Meuse, and it was given them because the first specimen ever found was taken from the quarries under the city of Maestricht, on the River Meuse. For this information, and for much more as to the anatomy of the Kansas mosasaurs, I am indebted to Dr. Williston’s splendid work in Volume IV of the University Geological Survey of Kansas: Paleontology, Part I; although, of course, I obtained most of my knowledge from the hundreds of specimens which I collected myself.
Among these are four especially fine specimens, nearly complete, of the flat-wristed Platecarpus coryphæus Cope. One of them I sent to the Iowa State University, with head, column, and limbs nearly in position, and still bedded in their native chalk. This fellow, who was over eighteen feet long, must have sunk so deep in the slimy mud of the ocean-bed that even the gases formed in his stomach could not lift his body to the surface. A second specimen was sent to the British Museum of Natural History, in London; a third to Munich, Bavaria, and a fourth to the Roemer Museum, in Hildesheim, Germany.
Fig. 9.—Ram-nosed Tylosaur, Tylosaurus dyspelor.
Restoration by Osborn and Knight. (From painting in American Museum of Natural History.)
Fig. 10.—Skull of the Flat-wristed Mosasaur, Platecarpus coryphæus.
(In the Kansas State University.)
This last specimen is the best I ever took from the Kansas chalk until 1907. It is twenty-five feet long. Unfortunately, the head was all washed away, with the exception of the mandibles and a few bones of the skull. The most remarkable feature of this specimen was the presence, for the first time in my experience, of the complete cartilaginous breastbone with the cartilaginous ribs, which are very rare. They were described for the first time from the noble Bourne specimen, by Dr. H. F. Osborn, of the American Museum.
This mosasaur, Platecarpus, is the most common species known, and is almost as large as the big Tylosaurus. It differs from the latter, however, in the shape of the short, strong paddles and the blunt rostrum. The skull in the illustration (Fig. [10]) is that of a very fine specimen, one of my discoveries, which was mounted by Mr. Bunker, of the natural history department in the Kansas State University. I have never seen a more complete skull, or one that shows the height so well, in any specimen, unless it is the little Clidastes velox, in the Kansas University collection. You will notice the triangular shape of the head, with the strong bones arching back to support the lower jaw by the pulley-like quadrate bone. Notice also that the suspensorium, instead of curving down so that its groove fits over the rounded edge of the quadrate, is straightened out. This is caused by its having been flattened and distorted, as nearly all fossils are, by the immense pressure to which it has been subjected. Observe the conical shape of the head in front of the eye-rim, terminating in the hard, blunt rostrum. It is believed by the authorities that a blow from this ram, delivered at full speed, would put an adversary out of commission.
But how did this creature feed itself, when all its teeth are for grasping, none for masticating? And how did it hold its prey, when it has no claw-armed fingers, only weak paddles for swimming?
In answering these questions, we shall describe two characteristics of the mosasaurs which differentiate them from all other reptiles.