﻿Vol. 66.~\ MEGALOSAVRUS BRADLEYI. 113 



The shape of the left ramus of the mandible is completely shown, 

 but its hinder half is so much fractured that its constitution cannot 

 be exactly determined. The very slender dentary bone (d.) tapers 

 to a blunt point at the symphysis, where its four anterior teeth are 

 relatively small. It gradually deepens in its hinder half, and 

 its >-shaped sutural union with the angular (ag.) is distinct below 

 the small oval vacuity (F.), which occurs behind it between the 

 angular and surangular bones. On its outer face may be observed a 

 sparse longitudinal series of large nutritive foramina, those in the 

 hinder half being placed in a shallow groove which inclines upwards 

 posteriorly. The coronoid region is the deepest part of the mandi- 

 bular ramus, its maximum depth equalling a seventh of the total 

 length ; but its upper margin is only gently rounded (not raised 

 into a process), and it rapidly tapers behind to the very low 

 articulation for the quadrate bone. 



Most of the teeth are well displayed, and exhibit a tendency to 

 replacement alternately, as in crocodiles. Those of the premaxilla 

 are remarkable for their very small size, the height of the third or 

 largest tooth not quite equalling half the height of the largest 

 maxillary tooth. They are thick, round or oval in cross-section, 

 very slightly recurved, and only compressed to a sharp edge 

 behind, where they are regularly serrated to the base. Their 

 outer face is marked by a few slight vertical flutings, which are best 

 seen in the third tooth (PL XIII, fig. 2). The fourth or hindmost 

 premaxillary tooth is not exserted ; but the other three are com- 

 pletely in functional position, and gradually decrease in size forwards. 

 The foremost tooth of the maxilla, which is seen in its broken 

 socket, is as stout and small as the premaxillary teeth ; but all the 

 others of the series are much laterally compressed and recurved, 

 with a sharp serrated edge behind and a blunter, more finely 

 serrated edge in front. The largest teeth of the mouth are those 

 within the front half of the maxilla ; while those in the hinder 

 half of the same bone rapidly become smaller, until the hind- 

 most (shown only in impression) are very short and broad. The 

 three teeth preserved at the symphysial end of the mandible are as 

 small as the premaxillary teeth opposed to them, and apparently 

 similar ; but the other teeth of the dentary, so far as shown, 

 resemble the principal teeth of the maxilla in shape, and only 

 differ in being much smaller. All the serrations of the teeth 

 (PI. Xltl, fig. 3 b) are in regular series, blunt, and not inclined 

 upwards. 



On the rock below the mandible occurs the long and slender curved 

 "bone shown in PI. XIII, fig. 4. It is smooth, and only impressed by 

 a shallow longitudinal groove near its thicker end. Both its ends 

 are indefinite, as if originally cartilaginous. It is probably one 

 of the hyoid elements, which have already been noticed by Marsh 

 in Ceratosaurus. 



As shown by the discoveries in North America, all the skulls of 

 Megalosauria are remarkably similar, and it is difficult to find 

 generic differences between them. In fact, they can scarcely be 



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