Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/237

 maxilla curves upwards, so as to leave a deep notch between itself and the downwardly curved, beak-like anterior termination of the snout, which appears to be formed altogether by the praemaxillae. Into this notch the surface of the matrix indicates that curved upward processes of the mandibular rami fitted. Whether these processes, and those of the praemaxillae which projected between them over the mandibular symphysis, ended in teeth, or not, cannot be determined, as the extremities of the premaxillary processes are broken away, and the mandibular processes are represented only by impressions. But it is very likely that such was the case, if we may judge by the analogy of some existing lizards (such as Uromastix spinipes), which present a very similar arrangement of the extremities of the jaws. The two praemaxillae, however, are confluent in this lizard, while they are distinct from one another in Hyperodapedon.

From the dentary margin the outer surface of each maxilla inclines rapidly outwards, so that, even making allowance for partial artificial depression, the measurement from the outer margin of one orbit to the other is nearly double that between the dentary margins of opposite sides. This conformation of the upper jaw also obtains, though to a less extent, in Uromastix.

The orbit was large ; but its form cannot be accurately determined, almost the whole of the roof of the skull being absent. There is a cast of a strong supratemporal zygomatic arch, formed in part by a prolongation backward of the jugal, and in part by a forward extension of the squamosal, as in Uromastix. Clear indications of a strong quadrate bone and of a pterygoid are also visible ; and the remains of a long slender left cornu of the hyoidean apparatus lies parallel with the left ramus of the mandible, on the ventral face of the skull. No remains of any infratemporal zygomatic arch, such as is found in Chelonia, Crocodilia, and Aves, are visible ; but the existence of such a structure is very probable from the analogy of Rhynchosaurus.

The remains of two broad plates of bone, not less than 3-1/2 inches in length, with concavo-convex surfaces and a curved free edge, which lie near the anterior end of block No. 1, most likely represent the coracoids. A large impression of about the same length, which must have been formed by a bone which was thin at both edges, thin and expanded at one end, and thick, with an excavated terminal surface, at the other, lies near one of the coracoids ; and I take it to have been made by a scapula. What I suppose to be a cast of the corresponding bone of the other side lies upon block No. 2; and there are sundry scattered imperfect impressions of limb-bones, indicating a fore leg of no great size. The right pubis and ischium have left very distinct impressions of their dorsal surfaces at the hinder end of block No. 1. In general form these bones resemble the corresponding bones in existing lizards ; and the pubis has a great prepubic process, as in the latter. But the pubis and ischium of the same side seem to have united on the inner as well as on the outer side of the obturator foramen, which appears to have been proportionally much smaller than in existing Lacertilia.