Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/90

4 I pointed out the peculiar value of the skull, which arose from the nearly entire condition of the præmaxillary hones, which last had, up to that time, been displayed by no Dinosaurian fossil, except, perhaps, Compsognathus. I further drew attention to the singular fact that the incisor teeth, or those contained in the posterior moiety of each præmaxilla, were totally different in shape from the maxillary teeth; and that the anterior moiety of the præmaxilla was beak-like and edentulous. Moreover I expressed the opinion that while the affinity of the reptile with Iguanodon was clear, the extent of that affinity could only be determined by further critical comparisons.

I lost sight of the specimen for a long time; but, some months ago, hearing that it was in Mr. Fellows's keeping in London, I requested Mr. Pox's permission to subject it to more careful study. That permission was very readily and liberally accorded by Mr. Fox, and I now offer the results of this further work to the Society.

The skull (Pl. I. fig. 1), when entire and undistorted, must have had a length of rather less than four inches (probably about 3⋅8 or 3⋅9). The greater portion of the roof and of the right upper maxillary apparatus, with a part of the occipital surface, are displayed. The whole left nasal bone is exposed, together with part of the left præmaxilla and a portion of the left ramus of the mandible.

Two relatively large supratemporal fossæ, each about three-quarters of an inch long and four-tenths of an inch wide, lie at the sides of the parietal region, which is somewhat narrow in the middle, but expands at each end. The parietal bones (Pa) are a good deal injured, but they appear to have inclosed an oval median parietal foramen. In front, they unite by a transverse suture with the large frontal bones (Fr). Each of these is 1⋅4 inch long, 0⋅5 inch broad behind, and rather narrow in front, flattened though slightly concave from side to side, and somewhat convex from before backwards. The inner edges of the two frontal bones are a little raised where they unite in the frontal suture. The nasal bones (Na) are very large, being as long as the frontals, and very nearly as broad behind, where they are flattened and continue the direction of the roof of the skull. Anteriorly they narrow; and their outer surfaces, becoming convex, look somewhat outwards. Each nasal bone ends by a deeply concave rounded free margin, which bounds the nostril (N) above, and sends down a slender process on each side. The inner of these bounds the greater part of the inner side of the nostril, and lies upon, and internal to, the anterior ascending process of the præmaxillary bone (Pmx). The outer, in like manner, applies itself to the anterior edge of the ascending process of the maxillary, and forms a part of the outer boundary of the nostril.

The præmaxilla is a very large and remarkable bone. The body, or dentigerous portion, is 0⋅8 inch long and 0⋅3 inch high, from the alveolar edge to that which bounds the nostril below. The greater part of the outer surface of the bone is smooth; but towards its anterior end it becomes rugged and pitted, and seems to have been produced downwards and forwards into a short beak-like process.