The radius is about the same width proximally as distally. The curvature of the shaft is approximately alike on both sides. Distally the surface is rounded for articulation with the radiale and perhaps the intermedium. The proximal end of the ulna is similar to that of the radius but is slightly larger. Posteriorly, there is a short, broad expansion resembling the entepicondyle of the humerus, and even more nearly like the postaxial flanges in a crossopterygian fin. The ends of the radiale are expanded and rounded, the entire bone being approximately twice as long as wide. The three sides of the intermedium are similarly convex. The surface of this bone is unfinished, showing that it must have been embedded in cartilage. The ulnare is conspicuously similar to the ulna in bearing a posterior hooklike expansion, and is larger than the radiale. The four metacarpals are slightly expanded proximally and distally. Although measurements of length and width are tabulated below (Table 2), we are not certain of the sequence of these bones in the row. The dimensions of the two proximal phalanges are alike. The shape of these elements is similar to that of the metacarpals. The two terminal phalanges are somewhat triangular in shape, the lateral edges being concave and the proximal convex. TABLE 2.--APPROXIMATE MEASUREMENTS OF THE FORELIMB (in mm.) --------------------------+------------------------------------------- | Dimensions +----------+-------------------------------- ELEMENT | | Width | Length +----------+----------+---------- | | Proximal | Midway | Distal --------------------------+----------+----------+----------+---------- Humerus | 16.0 | 5.0 | 2.0 | 7.5? Radius | 9.0 | 4.0 | 1.5 | 3.5 Ulna | 8.5 | 4.5 | 1.5 | 3.5 Radiale | 3.0 | 2.0 | 1.5 | 2.0 Intermedium | 1.5 | -- | 2.0 | -- Ulnare | 3.5 | 2.0 | 2.0 | 2.5 Metacarpal A | 4.5 | 2.5 | 1.0 | 2.0 Metacarpal B | 4.5 | 3.0? | 1.5 | 2.5 Metacarpal C | 4.0 | 2.0 | 1.5 | 2.0 Metacarpal D | 3.5 | 2.5 | 1.0 | 1.5 Proximal Phalanx A | 2.0 | 1.5 | 1.0 | 1.5 Proximal Phalanx B | 2.0 | 1.5 | 1.0 | 1.5 Terminal Phalanx A | 1.5 | 1.5 | 1.0 | 1.0 Terminal Phalanx B | 1.5 | 1.5 | 1.0 | 1.0 --------------------------+----------+----------+----------+---------- COMPARISONS AND DISCUSSION