This bone is intermediate in character between the corresponding bones of _Testudo_ and _Emys_. The head is longer and narrower than in the former genus; it is implanted on a short, distinct neck, and is strongly convex in both directions. The articular surface extends to the base of the internal tuberosity. The tuberosities, especially the external one, are very large and thick. The external rises above the head, and resembles that of _Emys_ in shape. The fossa separating the tuberosities is comparatively narrow. The shaft is much like that of _Emys_, but is somewhat more strongly curved; not so much, however, as in _Testudo_, and the distal end is not so much flattened. The anconeal fossa is wider and deeper than in either genus. The trochlea is broad, and divided by an obscure groove into a small and convex radial face, and a nearly plane (transversely) ulnar face. The condyles are prominent and rugose. Found near Dry Creek. EMYS. Emys wyomingensis, Leidy. Cont. to Ex. Vert. Fauna, p. 140. Represented by six perfect shells from Cottonwood and Dry Creeks, and Henry's Fork, and a shoulder girdle from Cottonwood Creek, which is provisionally referred to this species. This species, when adult, was upward of a foot in length, and in the composition of the shell, number of scutes, etc., resembled the living species of the genus. _The Shoulder Girdle_ has the form characteristic of the _Emydidæ_, but presents some peculiarities. The scapula is short, not being as long as the coracoid, and is not so straight or cylindrical as is usual in _Emys_; but is compressed, and somewhat recurved, and tapers towards the upper extremity, which is marked by a smooth rounded facet for the cartilaginous supra-scapula. The precoracoid is long, sub-cylindrical at its origin, but becomes broad and flat distally; at the extremity it is longitudinally striated. The proximal end is flexed forward at an obtuse angle, and is expanded to form the long suture with the scapula and coracoid. It contributes considerably to the glenoid cavity. The coracoid is remarkably long, and after leaving the sutures with the other elements of the girdle, becomes very broad and thin. This is most marked distally. The anterior border is thickened, and the bone is slightly concave on both surfaces. The three parts of the shoulder girdle are united by distinct bony symphyses; they differ from some of the modern species, in which there is only a ligamentous union between the coracoid and the other parts. It presents a further difference in the long and slender neck which is formed by the flexing of the precoracoid, and in the shallow and subcircular glenoid cavity. The short scapula and long coracoid would indicate a species with a low, broad carapace, as was probably the case in _E. wyomingensis_, though much difficulty has been experienced in determining this point, owing to the distortion of the specimens. _Measurements._