| M. | |
| Length of rib without curvature | ·571 |
| Length of rib with curvature | ·739 |
| Width of rib just below head | ·049 |
| Width at muscular attachment | ·063 |
| Vertical diameter of larger facet of capitulum | ·039 |
Scapula ([Plate VIII.], Fig. 1).—The scapula is subtriangular, with the pre-scapular border as base, and the apex half way up the postscapular.
On the external side the pre-scapular fossa is concave antero-posteriorly, and plane in the direction of its length; it is very thin in the middle, but becomes heavier at the lateral border. The postscapular fossa is larger and less concave; both fossæ, as they approach the upper border, gain greatly in thickness.
The spine rises from the supra-scapular border, and extends to within an inch from the glenoid cavity. It is decidedly antroverted; thickest and highest near glenoid cavity; thinnest and lowest in the middle, expanding again at its upper extremity; its acromio-scapular notch is long and shallow. The acromion is rudimentary.
The coracoid process is a low, rugose tuberosity; the coraco-scapular notch is short and low.
The internal surface of the scapula has a large, smooth median ridge, extending the whole length of the bone, separating it into slightly concave fossæ. About two thirds up, the median ridge sends obliquely up two branches, forming a V, superimposed upon the main ridge; but these disappear before they reach the upper extremity. The whole inner surface is curved outward, presenting a concave appearance throughout.
The glenoid cavity is deep, ovoid in form, with its greatest diameter fore-and-aft, and its smaller end behind.
The resemblance between the scapula of Uintatherium and that of the Proboscidea is more closely marked than in any other corresponding bones. The chief points of similarity are: first, the subtriangular shape; second, the same relative proportions between the fossæ; third, the antroversion of the spine; fourth, the glenoid cavity looking directly down. The marked points of difference may be summed up as, first, in the dissimilar proportion of the glenoid cavity; second, the great thickening of the spine at its upper and lower extremities; third, in the high, shallow acromio-scapular notch; fourth, in the longitudinal concavity of the internal surface.
Measurements.
| M. | |
| Extreme length of scapula | ·42 |
| Extreme length of spine | ·31 |
| Extreme thickness of spine at upper margin | ·098 |
| Extreme height of spine | ·109 |
| Basal width of proximal end of spine | ·032 |
| Basal width of distal end of spine | ·030 |
| Basal width of middle part of spine | ·011 |
| Length of glenoid cavity | ·149 |
| Width of glenoid cavity | ·096 |