Champsosaurus annectens, Cope, 1876

Lambe L. M., 1902, New genera and species from the Belly River Series (mid-Cretaceous), Geological Survey of Canada Contributions to Canadian Palaeontology 3, pp. 25-81 : 45-46

Champsosaurus annectens , Cope.

Vertebrre, Leidy. 1860. Trans. Amer. Philos. Soc. Extinct Vertebrata from the Judith river and Great Lignite formations of Nebraska, p. 147, pi. 9, figs. 56-61.

Champsosaurus annectens , Cope. 1876. Proc. Acad. Nat. Sci. Philadel., p. 351 This species, the type of the genus, is represented by a large number of vertebrae, none of which were found together in their proper relative positions, but in a few in- stances, a number, collected within limited areas, may represent incomplete series.

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The vertebrae consist of cervicals, dorsals, caudals and some from the sacral region. The anterior dorsals are keeled below, in the dorsal series the angularity gives way to a rounded lower surface, the sacrals are depressed and the caudals, early in their series, become laterally compressed. The posterior, inferior ends of the caudal centra present facets for chevron bones; in one anterior caudal, in particular, they are conspicuous with a pronounced enlargement of the centrum in their vicinity. In most of the dorsal vertebra3 the neural arches have become detached, in the caudals the base at least is generally intact. The zygapophyses are well developed. The articular faces of the centra in the caudals are slightly concave, those of the dorsals are plane. There is a considerable variation in the size of the vertebraj.

It is altogether probable that more than one species is represented.

The following measurements in mm. are taken from a number of centra found with others within a limited area:

	Cervical.	Dorsal.	Sacral.
Length of centrum	13;5	17-0	17-0	18-5	15-5	130	13-0
Height of articular face	13-5	15	130	12-5	110	70	5-3
Breadlh	13-5	17-0	15	14-5	100	60	4-5

A large dorsal from Mackay creek has the following dimensions: length of centrum, 27'0 mm., height of articular face, 220 mm., breadth of articular face, 23"0 mm.

Ghampsosattrus is known, also, by comparatively complete skeletons from the Lower Eocene of Rheiras, France, and Erqueliuues, Belgium.

Belly Eiver series. Red Deer river, 1897, 1898 and 1901.

Vertebrae were collected at Mackay creek.near "Walsh station on the line of the C. P. R., in 1880, by Professor John Macoun; on Belly river, N. W. T. (Nos 40 and 41), in 1881, by Dr. G-. M. Dawson: and at Ross coulee, near Irvine station, by Mr. T. 0. Weston, in 1884.