No. 10 shows the proximal surface well; portions of it are seen in Nos. 4, 5, 6, 8, 9, 11, and 12. The distal surface is best exhibited in No. 1; portions of it are shown in Nos. 2, 3, 5, 7, 8. No. 13 is an impression taken from the proximal sur&ce of a distal carpal to show its correspondence with distal surface of the proximal carpal. The bone is proximally of an irregular oblong form, being five sided, and much broader towards the inner end than towards the outer end. The two ends are sub-parallel, and rather obliquely connected on one side by a nearly straight border more than twice as long as the shorter end. The other limits of the sub-parallel ends are connected by two concave borders meeting in a well rounded convexity, which is near to the broader inner end. The proximal surface of the bone is flattened, and may be divided into a sub-rhomboid space, adjacent to the shorter of the sub-parallel ends, which is moderately concave in the long axis of the bone and slightly convex transversely, and an oblong space adjacent to the longer of the two ends. This is separated from the sub-rhomboid space, toward the straight side of the bone, by an elevated ridge sub-parallel with the ends. It is directed towards the convexity on the opposite side, in which the long and short concave parts meet, but after half crossing the bone it becomes forked in a U shape, and less elevated; the smooth unarticular included space shows an oval pneumatic foramen, which varies in size with the different species. The region between this Y-shaped ridge and the longer of the two ends, is sub-reniform, slightly concave in its long diameter, and deeply concave in the short diameter, exactly corresponding in form with the articular surface already described as the distal end of the ulna. Also parallel with the long end of the bone are marks of an articular surface exactly corresponding with those described as the distal end of the radius; that is, at the convex angle of the angulated side is placed a hemispherical boss,' interior to which is a hemispherical concavity, and extending toward the straight side is the oblique smooth border of the sub-rhomboid area described. There still remains a space to be accounted for. This consists of a sub-quadrate area forming the corner of the bone made by the concave side and the shorter outer end; it is made up of an inner concave part separated from the radial articulation by a ridge, and an outer convex part constituting the shorter end of the bone. This carpal is moderately compressed from the proximal to the distal side, except towards the shorter end of the bone, being there prolonged distally into a wedge-shaped process, showing at its termination marks of a powerful muscular attachment. The outer lateral surface is of variable antero-posterior extent.