336 PROF. OWEN ON THE SKULL OF MEOALOS1URFS. 



dental series extends beneath both nasal and orbital vacuities, but 

 for a less extent in the carnivorous than in the herbivorous Lacer- 

 tians. Scelidosaurus, in the degree and kind of its facial ossifica- 

 tion, repeats the mammalian character exemplified in Iguanoclon *. 



Of the subjects of the present paper the first block of lower 

 oolitic freestone includes a great proportion of the right side of the 

 facial part of the skull (Plate XI. fig. 1). The missing parts are 

 the fore end of the premaxillary, 22', and the hind or suborbital 

 end of the maxillary, 21' ; the upper and hinder pointed termination 

 of the facial process, /, of the maxillary, is likewise wanting. 



The length of this facial fossil is 1 foot 3| inches ; its height from 

 the upper angle, a, of the maxillary process to the tip of the sub- 

 jacent tooth t, in situ, is 9 inches. 



Of thepremaxillaryare preserved part of the nasal process, 22", and 

 so much of the alveolar part, 22, as lodges two fully developed and 

 protruded teeth and the socket of a third : an intervening part of 

 the bone has been chiselled away to admit a wedge for the quarrying- 

 operations : the length of the preserved premaxillary nasal process, 

 22", is 4 inches, the breadth of its base is 1 inch ; it narrows to its 

 apex, being limited to the fore and under part of the large bony 

 narial vacuity, n, in the present specimen. 



So much of 22" as is preserved forms rather more than one third 

 of the lower border of the external nostril, n, the rest of that border 

 with the hinder boundary, 0, being contributed by the maxillary, 

 21". The limitary suture between these bones is distinct. 



The preserved length of the alveolar part of the maxillary, 21, 21', 

 is 1 foot : the upper border of this part contributes an equal share 

 to the large narial (n) and orbital (0) vacuities ; but these portions of 

 such tooth-bearing part of the upper jaw combine to form the base 

 of the facial process, a f, which is between four and five inches in 

 extent : its breadth, at one inch above the border line, 22", is three 

 inches ; this breadth is nearly preserved to the angle, a, about six 

 inches above the alveolar border, at which angle the maxillary is 

 continued backward, above the fore part of the orbit, gradually 

 narrowing to the point, /', which is here broken off. 



Much of the outer wall of the alveolar part of the maxillary 

 adheres to the block of freestone in which the counterpart of the 

 above- described cranial fossil is preserved : but this counterpart 

 shows only the impressions of the teeth, which are well preserved 

 in the block containing the chief part of the fossil. Of these teeth 

 four are premaxillary, the rest maxillary. 



The teeth closely repeat the characters of previously described 

 dental evidences of Megalosaurus BucTdandi. 



Of the foremost preserved premaxillary tooth, 2 inches of the crown 

 remain, with half an inch of a mutilated base ; the next tooth is re- 

 presented by a smaller protruded apical part of the crown. The socket 

 of the larger intervening tooth is broken away with the implanted 

 tooth-root, exposing the pulp-cavity. The impression of the broken 



* Monograph in the volume of the Palasontographical Society for the year 

 1861, tab. v. fig. 1. 



