The giants of the Pythonomorphs of Kansas have been called _Liodon proriger_ (Cope) and _Liodon dyspelor_ (Cope). The first must have been abundant, and its length could not have been far from sixty feet, certainly not less. Its physiognomy was rendered peculiar by a long projecting muzzle, reminding one of that of the blunt-nosed sturgeon of our coast, but the resemblance was destroyed by the correspondingly massive end of the branches of the lower jaw. Though clumsy in appearance, such an arrangement must have been effective as a ram, and dangerous to his enemies in case of collision. The writer once found the wreck of an individual of this species strewn around a sunny knoll beside a bluff, and his conic snout, pointing to the heavens, formed a fitting monument, as at once his favorite weapon, and the mark distinguishing all his race. Very different was the _Liodon dyspelor_, a still larger animal than the last, with a formidable armature. It was indeed the longest of known reptiles, and probably equal to the great finner whale of modern oceans. The circumstances attending the discovery of one of these, will always be a pleasant recollection to the writer. A part of the face, with teeth, was observed projecting from the side of a bluff by a companion in exploration, (Lieut. Jas. H. Whitten, U. S. A.), and we at once proceeded to follow up the indication with knives and picks. Soon the lower jaws were uncovered, with their glistening teeth, and then the vertebræ and ribs. Our delight was at its height when the bones of the pelvis and part of the hind limb were laid bare, for they had never been seen before in the species and scarcely in the order. While lying on the bottom of the cretaceous sea, the carcass had been dragged hither and thither by the sharks and other rapacious animals, and the parts of the skeleton were displaced and gathered into a small area. The massive tail stretched away into the bluff, and after much laborious excavation we left a portion of it to more persevering explorers. The species of _Clidastes_ did not reach such a size as some of the _Liodons_, and were of elegant and flexible build. To prevent their habits of coiling from dislocating the vertebral column, these had an additional pair of articulations at each end, while their muscular strength is attested by the elegant striæ and other sculptures which appear on all their bones. Three species of this genus occur in the Kansas strata, the largest (_Clidastes cineriarum_, Cope) reaching forty feet in length. The discovery of a related species (_Holcodus coryphæus_, Cope) was made by the writer under circumstances of difficulty peculiar to the plains. After examining the bluffs for half a day without result, a few bone fragments were found in a wash above their base. Others led the way to a ledge forty or fifty feet from both summit and foot, where, stretched along in the yellow chalk, lay the projecting portions of the whole monster.