144 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 13, 



The pubis and ischium occupy a space equal in length to four 

 vertebrae, which is a proportion very similar to that which obtains 

 in existing Lacertilia. 



A distinct impression of the right femur is left almost in its na- 

 tural position. It is a nearly straight and very strong bone, which 

 is 4-7 in. long, or equal to more than five vertebrae in length. The 

 femur has a similar proportional size in Monitor and Iguana. Im- 

 pressions of the proximal ends of the tibia and fibula are visible, in 

 such relation to the femur as shows them to have undergone very 

 little disturbance. 



No certain indication of the character of the feet is discernible. 



The general arrangement of the teeth has been described. The 

 downwardly convex dentigerous edge of the maxilla is 2-75 in. long, 

 and appears to have carried about eighteen (or perhaps more) teeth, 

 of a conical form and very closely set. The outer surface of the 

 maxiUa, from the dentigerous edge to the lower boundary of the 

 orbit is fully an inch high, and is excavated and inclined outwards 

 with a very peculiar curvature. 



The dentigerous edges of the opposite maxillae converge towards 

 one another at an angle of about 45°, and then become parallel as 

 the snout narrows to its termination. 



No suture can be distinguished upon the roof of the mouth, be- 

 tween the maxillae and the palatine bones, though the boundary line 

 between the two is probably indicated by the groove into which the 

 dentigerous edge of the mandible bites. The roof of the palate is 

 therefore formed by a broad plate of bone, which may be called 

 palato-maxillary, as it is constituted by the conjoined maxillary and 

 palatine. Anteriorly this plate has a width of not more than 

 0*35 in. internal to the groove, but it widens posteriorly to 0-7 in. 

 Its inner edge is convex towards the middle line, roughly following 

 the course of the dentigerous edge. For their anterior halves the 

 two edges of the palato-maxillary bones seem to be separated by 

 only a small interval ; but posteriorly they diverge widely ; whether 

 the interspace was occupied by the pterygoids, or not, cannot be 

 ascertained. 



The palato-maxillary plate on the inner side of the groove bears 

 three (or perhaps four) longitudinal series of conical teeth, the largest 

 of which are about 0*1 in. in diameter at the base. The posterior 

 edge of the palato-maxillary is abruptly truncated, smooth, rounded, 

 and shghtly concave backwards. 



It is upon this part of the organization of Hyperodajpedon that 

 Dr. Lloyd's specimens throw such important light. One of them, which 

 is smaller and more perfect than the other (fig. 1, a, b, c, d, e), exhibits 

 nearly the whole of the characteristically convex dentigerous margin, 

 and excavated and outwardly inclined outer face, of the palato-maxil- 

 lary of Hyperodapedon. Its posterior margin is smooth and rounded 

 below, exhibiting the natural termination of this part of the bone. 

 The inner surface is also quite smooth, and could not have united 

 suturally with any other bone. The anterior end of the bone is 

 broken off transversely ; but probably very little of it is lost. As it 



