Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/47

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Pr. A. N. S., Phila, 1851, 325, 1854, 72. Cretaceous Rept. N. A. 25, tab. 00.

This species has hitherto been known from vertebræ only. In connection with vertebræ of this species, I procured a long bone which has a near resemblance to the of Plesiosaurus, It indicates a paddle for motion in the water, as has already been mentioned.

The breadth is equal to 1⅗ the length. It is distal compressed, but thick and with rounded margins. The proximal portion is slightly reverted to the, and compressed nearly at right angles to the distal extremity. The condyle is flattened and oval in circumference. The tibial and fibular articular faces form a strong angle with each other, and are pitted for the cartilaginous articulation.

It is seen, therefore, that this bone is remarkably robust, much more so than in the Plesiosauri of adult age. That the individual to which it pertained is not mature, appears from the dorsals accompanying, in which the neural arch is not fully coössified to the centrum. We can regard the species as a robust and powerful animal, in which bulk is more prominent than length.

The centrum is much constricted medially and the diapophyses are given off from the neurapophyses, the lower margin corresponding with that of the bottom of the neural canal. This specimen is from Barnesboro, and was submitted to me by Prof. Cook, State Geologist.

Locality: the Cretaceous Green Sand of New Jersey; upper bed. Brimosaurus grandis, Leidy, Proceed. Ac. Nat. Sci., 1854, 72; tab. I., II.

From Cretaceous of Clark County, (near Greenville).

I have not seen any part of this, the largest species. It is, from Leidy's figures and description, distinguished by the relatively greater width and height of its vertebra, and has been therefore a shorter and more massive animal than its. As nothing beyond Leidy's description is known of it, I append the latter.

It was represented by vertebra from near Greenville, Clark County, Arkansas. They had been kindly loaned by W. T. Roberts, an agent of the Arkansas Mining Company, who had discovered them with numerous others. Dr. L. stated that, in his visit to St. Louis, Mr. Alb. Koch, the industrious collector of fossil remains, had exhibited to him a collection of bones from the same State, and apparently of the same animal, which he was on the eve of sending to. The specimens are remarkable for the robust transverse processes, which project laterally from the lower part of the body, and terminate in a large facet for the articulation of a rib. The bodies are cylindroid, and are terminated by slightly concave or nearly flat articular surfaces. The sides of the body are moderately concave, and have an acute margin at the articular surfaces. On each side of a median prominence of the under side of the body a large foramen exists. These vertebra resemble those of Cimoliasaurus magnus from the