8 Mv. A. S. Woodward on some 



partly obscured by the crushing of facial bones upon it ; but 

 the four specimens in the Leeds Collection suffice to exhibit 

 all its elements. The dentary bone (PI. I. fig. 1, d.; PI. II. 

 fig. 4 ; PI. III. fig. 2, d.) is comparatively insignificant, thin, 

 deep, and narrow, meeting its fellow in the middle line and 

 bearing a row of four large teeth. The greater portion of its 

 external surface is ornamented with tubercles, and it sends a 

 postero-inferior process underneath the large aiigular plate. 

 The latter plate (PI. II. fig. 5; PI. III. fig. '2, ang.) does not 

 extend upwards so far as the oral margin, but it completes 

 the hinder portion of the outer face of the mandibular ramus, 

 and its hinder ascending portion meets a small coronoid bone 

 [cor.) in a very wavy suture, which is frequently closed. The 

 upper portion of the coronoid bone is very thin and quite 

 smooth, and does not reach the tip of the great coronoid 

 process of the splenial. Indeed, the splenial element (PI. I. 

 fig. 1, spl. ; PI. II. fig. 3 ; PI. III. fig. 2, spl.) is exposed on 

 the outer aspect of the entire margin of the mandibular ramus 

 behind the short oral border of the dentary. It is much the 

 largest and stoutest bone in the jaw, meeting its fellow of the 

 opposite side at the symphysis and completely covered to the 

 base of its coronoid elevation with a pavement of teeth. The 

 articular bone (PI. I. fig. 1, art.), on the inner face of the 

 angular and apparently distinct, is always distorted by 

 crushing, though considerably ossified. 



Dentition. 



Teeth are confined to the vomer, splenial, premaxilla, and 

 dentary. They are all hollow, with a short base firmly anchy- 

 losed to the supporting bone. Certain displaced and unusually 

 coloured dental crowns are more suggestive of the existence 

 of successional teeth than any evidence the present writer 

 has hitherto observed ; but there is still no conclusive proof 

 of such displacement of the worn teeth. Of the prehensile 

 front teeth only one is preserved in the right dentary of no. 24 

 (PL II. fig. 4) ; its base is elevated, while the crown is trans- 

 versely elongated and chisel-shaped, convex on the outer face, 

 concave within. As already mentioned, each premaxilla bears 

 three of these teeth, while each dentary has four, all about of 

 equal size. The oral surface of the vomer (PI. I. fig. 1 h ; 

 Pi. II. fig. 2) is flat and bears three principal longitudinal 

 series of teeth, one median and a symmetrical pair on the 

 lateral margins. The lateral teeth are not much inferior in 

 size to those of the median series, but in the anterior half of 

 the bone there is an intermediate pair of rows of teeth scarcely 



