Notwithstanding the opinions of eminent German philosophers to the contrary no reptile has a carpus comparable to that of the Pterodactyle. If some of them have two rows of bones and a pisiform bone, so have mammals, and the mammalian arrangement is not more like the Ornithosauria than is that in Reptiles.
| Case. | Comp. | Tablet. | Specimen. |
| J | b | 5 | 1 3 |
METACARPAL BONE.
[Pl. 6.]
The illustrations of this bone comprise 31 specimens. Nos. 1 to 15 are examples of the proximal end, and Nos. 16 to 31 show the distal trochlear end of the bone. No. 1, which is nearly entire, gives the form and proportions of the wing-metacarpal in one species, but a knowledge of its variableness in German forms would guard against an assumption that all the other Greensand species were to be restored on the plan of this example. It is 35/8 inches long, to which three-eighths of an inch may be added for the distal articulation, making the length up to 4 inches. The proximal end is not well preserved, but in its wide measurement is 5/8ths of an inch; the distal end in the same measurement is about 3/8ths of an inch. A large example from the Chalk, in the Museum of C. Moore Esq. of Bath, shows the bone more attenuated distally. No. 1 is compressed so as to be oblong in section at the proximal end, and ovate in the middle of the shaft, which is slightly smaller than the distal end. One of the lateral outlines is straight; the other is concave. The bone is straight. In No. 30 the shaft where thickest measures less than 1/4 of an inch, becoming nearly circular in section. The shaft of No. 31 measures nearly an inch in width at its distal end, rather more than half an inch in thickness. No. 10 is 11/2 inch wide at the proximal end and 7/8ths of an inch thick. No. 9 would not have measured less when perfect than 21/2 inches over the proximal end, so that if it had the proportions of No. 1 it would have measured when entire not less than 16 inches in length.
The Proximal End.
The proximal end has never been figured. Prof. Owen's figure pl. IV. fig, 4-5, First Supt. Cret. Rep. is probably part of a jaw, and not the wing-metacarpal. The articular surface is oblong with one corner rounded off so that the adjacent long and short sides become confluent on the exterior surface of the bone.
In the middle of the flat inside margin and extending proximally is a semi-cylindrical process, which is prolonged a short distance down the side of the bone as an elevated ridge. On the flattened articular end this process is bordered by a semicircular furrow which extends half-way across the bone, outside of which is a slightly convex semicircular band which extends to the outer margin of the bone, except towards the short side opposite to that one which rounds into the outer side, where there appears to be a narrow unarticular area. On the inside of the bone where the two ends of the semicircular proximal furrow terminate are two deep grooves which extend a short distance distally; they are both limited by inward extensions of the short sides of the bone, that crest being most developed in height and length which is toward the flattened short side. The outline which these modifications give to the inner side of the proximal surface is intermediate in form between the letters S and
.
The Distal End.