440 PROF. H. GOVIER SEELEY ON THE 



away from the teeth, backward and somewhat downward, so as to 

 increase the thickness of the bone to f of an inch ; this claw process 

 is, as preserved, |- of an inch long, concave in length on the inside, 

 compressed from above downward, so as to form a ridge in front, 

 and seen from above downward narrows very slowly : it may be iden- 

 tified as the jngal process. Something similar in Hypsilopliodon is 

 represented by Prof. Huxley (Quart. Journ. Geol. Soc. vol. xxvi. pi. 1. 

 fig. 1), and by Mr. Hulke (ibid. vol. xxx. pi. 3. fig. 1), though in that 

 genus the process appears to be longer, stronger, and directed upward. 

 This is a point of some importance, since in Scelidosaurus no such 

 process is developed. Hence doubt is thrown on the value of 

 Prof. Huxley's classification of the Dinosauria by their teeth ; for 

 while this genus by its teeth resembles the Scelidosauridse, it is 

 shown by this jugal process to have the temporal fossa and associ- 

 ated parts of the skull fashioned on the plan of the Iguanodontidse 

 (Quart. Journ. Geol. Soc. vol. xxvi. p. 34). 



The maxillary bone, which is compressed from side to side, exter- 

 nally is gently convex in length, while internally it is rather more 

 concave in length along the palatal border, so that the inner and 

 outer sides are not quite parallel. The rather oblique line along 

 which the horizontal palatal processes of the maxillary extended is 

 inclined downward and backward ; the inner surface of the bone 

 between this line and the alveolar margin is concave in depth. 

 Externally the bone is most convex from above downward, just in 

 front of the jugal process, which is prolonged forward as a convex 

 ridge, making the bone above it seem obliquely flattened and con- 

 vex, and making the bone below it- concave. But a little further 

 forward the bone is steadily convex from above downward, and the 

 convexity grows less till it is obscured in the ridges at the base of 

 the nasal process. The external convexity causes the bone to ter- 

 minate above and below in a sharp ridge. 



Planning along the lower external alveolar border of the bone, in 

 the usual position of the dental foramina, is a series of unusually 

 large perforations (see figs. 1 & 3), one corresponding to each tooth. 

 They are larger than in the British-Museum specimen of Terato- 

 saurus, or the maxillary of Megcdosaurus, figured by Prof. Huxley 

 (Quart. Journ. Geol. Soc. vol. xxv. pi. 12). The foramen above 

 the last tooth is not preserved ; the third foramen is an eighth of 

 an inch from the palatal border, and displays a young successional 

 tooth descending in the socket behind it. The foramina get larger 

 from behind forward ; and other teeth are seen behind the sixth, 

 eighth, and eleventh; the twelfth is the largest foramen, resem- 

 bling a tooth-socket ascending into the jaw. A minute foramen 

 corresponds to the fourteenth socket ; but the fifteenth, sixteenth, 

 seventeenth, and eighteenth are in much thinner bone in front 

 of the jaw, and have no corresponding foramina; the sockets of 

 these anterior teeth are smaller than the others, so that they may 

 have presented a difference from the others, like that seen in 

 mammals between the premolar and molar teeth. It may be that, 

 by those anterior teeth having already come down, the foramina 



