Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/59

Rh verse of those ordinarily observed among reptiles, whence I was induced to consider it as the type of a peculiar group of high rank. This view is, of course, abandoned on a correct interpretation of the extremities. Leidy detected the error in this arrangement, and the correction extends to Cimoliasaurus as well.

This species is indicated by two vertebræ. The first resembles both the twelfth from the first dorsal of the cervical series of Cimoliasaurus magnus, or the fifth from behind, of the same of Elasmosaurus. Its large size, lateral longitudinal angle and small neural canal refer it with more probability to the latter genus. It appears to belong to a species possessing some of the peculiarities of the Cimoliasaurus magnus, having the quadrate form of the median cervicals of that animal, and lacking entirely the compression of the centrum and lateral concavity of the E. platyurus. The parapophyses are stronger and slightly more descending than in the fifth cervical of the latter, again resembling the more posterior vertebra of C. magnus Leidy. The bases of the parapophyses are more elongate than in the corresponding vertebra of C. magnus; the process was directed downwards at an angle of 45°, from the plane of the inferior aspect. The inferior plane is slightly concave, with two venous foramina, each in a strong groove on each side of a narrow median rib. The lateral surface is nearly vertical and slightly concave to the strong longitudinal angle. Above the latter the face is oblique concave for a width equal to that below. The articular faces are transverse ovals and slightly concave; their margin not prominent, nor ribbed on the lateral faces.

If we estimate this vertebra by the position of the lateral ridge to be about the eighth anterior to the last rib-bearing, which I call cervicals in this genus, the transverse diameter of this vertebra in C. magnus is two-thirds that of a dorsal with diapophyses near the middle of the centrum. Should the proportions have been similar in this species, the diameter of that dorsal would measure 6½ inches, indicative of the largest of American saurians. As, however, in the genus Elasmosaurus the disproportion between the sizes of the caudals and the dorsals is less than its ally, the latter have probably presented a diameter more like the same in E. platyurus.

A second vertebra from near the same part of the column of a much larger individual was obtained by Dr. Samuel Lockwood, superintendent of schools of Monmouth County, N. J., from Wm. Conovers' pit in the lower bed, near Marlboro, in that county. The diapophyses are directed downwards at an angle of 45°. The margins of the articular facts are not everted, while the inferior presents an open emargination medially. The two inferior foramina. are very large. The measurements are as follows:

In. Lin. 5 9 Width of articular surface, Depth do. do., 4 3 Length eentruni, 4 6

The name is not given under any supposition of restricted habitat, which may have been similar to that of the E. platyurus, but in view of the probability of its greater abundance where its remains have been found than elsewhere.

Our knowledge of this species is unfortunately confined to the two vertebræ above described. The first is from the lower cretaceous greensaud bed, from near Swedesboro, Gloucester County, New Jersey. It was found in a tailor's shop used as a block to secure a door.