But the most remarkable feature in these creatures was the arrangement for permitting them to swallow their prey whole, in the manner of snakes. Thus each half of the lower jaw was articulated at a point nearly midway between the ear and the chin, so as to greatly widen the space between the jaws, and Professor Cope thinks that the throat must consequently have been loose and baggy.
Professor Cope, however, in giving the name Pythonomorpha to this ancient group, has pressed his views too far, and dwelt unduly on their supposed relationship with serpents. Other authorities regard them as essentially swimming lizards, with four well-developed paddles; and this is probably the right view to take of them.
The following graphic account of the region where Professor Cope has discovered the skeletons of many sea-serpents, and of their habits and aspect when alive, is taken from his well-known work on the Cretaceous Vertebrata of the West.[36] After describing this region as a vast level tract between the Missouri and the Rocky Mountains, he says, "If the explorer searches the bottoms of the rain-washes and ravines, he will doubtless come upon the fragment of a tooth or jaw, and will generally find a line of such pieces leading to an elevated position on the bank or bluff, where lies the skeleton of some monster of the ancient sea. He may find the vertebral column running far into the limestone that locks him in his last prison; or a paddle extended on the slope, as though entreating aid; or a pair of jaws lined with horrid teeth, which grin despair on enemies they are helpless to resist; or he may find a conic mound, on whose apex glisten in the sun the bleached bones of one whose last office has been to preserve from destruction the friendly soil on which he reposed. Sometimes a pile of huge remains will be discovered, which the dissolution of the rock has deposited on the lower level; the force of rain and wash having been insufficient to carry them away."
[36] _Report of the United States Geological and Geographical Survey of the Territories_, vol. ii., 1875 (_Cretaceous Vertebrata_).
GROUP OF SEA-SERPENTS, ELASMOSAUR, AND FISHES.
Fishes, _Portheus_. _Elasmosaurus._ Length 50 feet. _Beryx._ _Clidastes._ Length 40 feet. _Osmeroides_, etc. _Mosasaurus._ Length 75 feet.]
