When the proximal epiphysis forming the heel comes away, it leaves a large sub-circular pit with a depressed narrow border.
Distal End.
On nearing the distal end, the angle of the inner side of the shaft becomes more depressed; and the articulation becomes an elongated oval, slightly convex transversely and convex in length so as to extend distally in a curve in such way that the articulation looks downward and outward from an aspect of the bone exactly opposite to the aspect from which the proximal articulation looks upward and inward. Hence the two articular surfaces are sub-parallel; but the distal one at its distal termination is bent inward, so as to make the adjacent lateral outline of the bone concave on the inside at its termination. The articulation does not cover the most proximal part of the distal surface.
| Case. | Comp. | Tablet. | Specimen. |
| J | b | 7 | 1—14 |
SECOND PHALANGE.
[Pl. 7.]
On this tablet are mounted 14 specimens. Nos. 1 to 9 are examples of the proximal end of the second phalange. If there were more than two phalanges, of which there is no osteological evidence, it is possible that proximal ends of succeeding phalanges may be included with these. They all however resemble each, other so closely as to lend no support to such a supposition. Nos. ?10 to ?14 have been mounted with the proximal ends because they appear to be portions of the middle of the shaft of the second phalange; they indicate a rapid distal attenuation, favouring the idea of there being but two phalanges.
The proximal end of the shaft has the outer side flattened, rarely concave, commonly slightly convex; the inner side being much more inflated, and not dissimilar in form to the inner side of the first phalange. Proximally the bone widens and one lateral outline extends outward in a curve, on the inner side of which, under the proximal articulation, is placed the pneumatic foramen. The elongated oval articular surface is concave from side to side and concave in length; it does not extend in length so far as the straight side outline, exterior to it being a crescentic flattened or convex area. The distal end attenuates more rapidly in some specimens than others, and appears in Nos. 11, 12, and 14 eventually to become cylindrical; but none of the specimens show its distal termination.
The phalanges of the wing-finger attain a grand development in length which is not paralleled in Birds, nor surpassed in Bats. In the Ostrich there are three phalanges in the wing-finger, while in Ornithopterus there are two joints, and in other German Pterodactyles four joints. The terminal joint in the Ostrich is a claw, but in Pterodactyle the terminal joint appears to be unarmed as in ordinary birds. The form of the bones in being compressed from side to side is more bird-like than bat-like. But the claws in their compression from side to side are more like the bat than the bird.
| Case. | Comp. | Tablet. | Specimen. |
| J | b | 7 | 1—14 |
DISTAL END OF METACARPAL
or Metatarsal Bones.
[Pl. 6.]