OOLITIC DINOSAURS. 171 



the bono as remains indicates a shallow longitudinal groove, nearly midway 

 between the upper and lower margins, and disappearing beneath the second tooth 

 in place ; anterior to this the bone shows a few irregular shallow pits, some of 

 which, occupied by matrix, indicate nervous or vascular foramina. In the same 

 block arc two fragments of, probably, the left ramus of the same jaw, each in 

 connexion with, or lodging, a portion of a fully developed tooth. 



A larger portion (fig. 3) which has been freed from another block, consists of 

 the anterior part of the left mandibular ramus of the same skull, 8 inches in length, 

 but wanting the symphysial end. On its outer side it repeats the longitudinal 

 gi^oove here extending backward three inches beyond the part interrupted in the 

 right ramus. In advance of this groove there are similar depressions and indica- 

 tions of the small nervo-vascular foramina. As the lower border of the present 

 fragment begins to bend upward at the anterior fracture, in a degree similar to 

 the fore end of the right ramus, I conclude that not more than an extent of two 

 to three inches are wanted to complete that end. The oblique fracture of the 

 bone here exposes the hollow base of the crown of a functional tooth, and on its 

 inner side is the partially calcified germ of the successor. 



The inner surface of the ramus (PI. 87, fig. 3) is flatter and smoother than the 

 outer. It is traversed by a deeper, narrower, and better-defined longitudinal 

 groove ; partially divided at its hinder half by a low linear ridge, indicative of the 

 groove having been traversed by two impressing soft parts, probably a nerve as 

 well as a vessel. The main groove becomes shallower and wider as it advances, 

 inclining from the middle to near the lower border of the inner surface. Part of 

 the suture between the splenial and dentary elements is here seen. 



The teeth indicated in the portion of the left ramus have been more or less 

 broken away, but answer in number and relative position to the entire ones in the 

 right ramus. The tooth rising to fill the space between the first and second is 

 more advanced ; and on the inner side of the present fragment are seen the crown- 

 tips of other successioual teeth, appearing at the inner side of the base of preserved 

 portions of the fully developed teeth. At the intervals of these rising teeth are 

 seen the " series of triangular plates of bone (b, h, fig. 3) forming a zig-zag buttress 

 along the interior of the alveoli, and fi-om the centre of each triangular plate, the 

 bony septum which crosses to the outer parapet, and thus completes the alveolus,"^ 

 well described in the type example. 



As respects the dental characters exhibited in the present series of fossils, I 

 find nothing to add to the Discoverer's original and graphic descriptions and to the 

 supplementary details afforded by the more complete mandible and teeth in the 

 private collection of the Duke of Marlborough at Blenheim. In the restoration of 

 the skull I have been guided by that of the largest existing carnivorous land-lizard 



^ Buckland, loc. cit., p. 395, pi. xl, fig. 1. 



