?NEURAL ARCH OF SACRAL VERTEBRA, ?VOMER.
Pl. 12.
| Case. | Comp. | Tablet. | Specimen. |
| J | c | 10 | 1—3 |
Frontal(?) Owen. Palæontographical, 1859
[Pl. 4, fig. 6, 7, 8.]
In 1859 Prof. Owen described with doubt as the Frontal of Pterodactyle, a symmetrical bone. A smaller but more perfect specimen has since been obtained for the Woodwardian Museum; and a fragment of intermediate size is in the rich collection of the Rev. T. G. Bonney. From the descriptions already given it is impossible for it to be the frontal. There is no proof that it is a skull bone. If of Pterodactyle the compressed lateral spaces could only be part of the nasal passages, or the impressions of a palatine or pterygoid articulation. And as the external surface of every specimen is keeled, and as the palatal surface of the upper jaw of every known Greensand Pterodactyle is keeled, and as the concavities slightly converge to the keel, it might be a bone from the under side of the head,—the vomer.
The smallest specimen is a compressed sub-semicircular bone 11/4 inch long, 9/16 inch high, and a 1/4 inch thick. The under surfaces converge to form a strong keel, which is flattened off behind. Above this, the posterior third of the bone is compressed obliquely to half the thickness, as though a bone had over-lapped this area on each side. If the oval spaces are nares, that bone might have been the pterygoid or palatine. Three-fifths of the remainder of the bone are taken up by the smooth oval depressions, which might be the inner walls of the nares; and above this is a margin of bone widening into the triangular compressed part in front, which, if the fossil is rightly determined, must have fitted into the posterior end of the maxillary or anterior end of the palatine bones.
A specimen collected by the Rev. T. G. Bonney is preserved on the sacral side of a left os innominatum with the keel downward. It appears to show a sutural surface from which an anterior part has come away. And if this specimen is compared with the neural arch of the sacral vertebra J.c.4.1, it will be found to correspond entirely. It is not impossible that c.10.1, 2 may be vomerine, and c.10.3 sacral, but there are no distinctive characters between the specimens to warrant such a determination.
| Case. | Comp. | Tablet. | Specimen. |
| J | c | 11 | 1—4 |
QUADRATUM.
[Pl. 11.]
and Quadrato-Jugal.
In the Woodwardian Museum are two distal ends of the quadrate bone and two other fragments showing the quadrato-jugal with it.