no. 1648. CERTAIN CARNIVOROUS DINOSAURS— HAY. 363 



Lambe has represented the angular as appearing hardly at all on 

 the outside of the jaw, but extensively on the inner side. What he 

 regards as the angular is almost certainly a long process of the artic- 

 ular, such as occurs in the lizards. If in Lambe's specimen there is 

 really a suture between the articular and the bone called by him the 

 angular the latter is a distinct prearticular. Quite certainly in Cera- 

 tosaurus the suture does not exist. Here the process reaches the fora- 

 men and a little below it (fig. 4, numeral 3). The cotylus of the artic- 

 ular, to suit itself to the quadrate, presents two grooves separated by 

 an oblique ridge. The articular extended but little behind the cotylus. 



What Lambe calls the presplenial, following Baur, the present 

 writer regards as a part of the true splenial, the other part being 

 what Lambe has recognized as the splenial. Thus the existence of the 

 suture represented by Lambe between his splenial and presplenial is 

 questioned. In the species described by Lambe the anterior end of 

 the splenial is very slender; in Ceratosaurus the splenial throughout 

 nearly its whole length rises close to the alveolar border of the dentary 

 and descends close to the lower border of the jaw. As it approaches 

 the symphysis its lower border seems to have risen somewhat. 



Fig. 1 represents a view of the left side of the skull, that which 

 best shows the bones of the palate. In the fossil the bones of the 

 palate stand nearly perpendicular, but without doubt this is to a great 

 extent due to crushing. They probably sloped upward and inward at 

 an angle of about 45 degrees, or more probably the} 7 formed a vaulted 

 roof for the mouth. 



The postero-inferior process of the pterygoid (fig 2, numeral 28) 

 joins the inner border of the quadrate at a point about 55 mm. above 

 the articulation of the latter bone with the lower jaw. The postero- 

 superior process rose to the upper end of the quadrate. Whether or 

 not the pterygoid articulated with the quadrate the whole distance 

 between the two points mentioned is somewhat uncertain. On the left 

 side of the skull a considerable part of the pterygoid from the middle 

 of the quadrate forward is broken away. Marsh neither mentions 

 any vacuity here nor does he represent it in his figure. On the right 

 side there is a gap between the two bones, extending about 55 mm. 

 along the border of the quadrate and forward from it less than 15 

 mm. It seems probable that in life this gap was filled in with bone. 

 This region is represented in the figure as it appears on the right 

 side. In Sphenodon the quadrate sends forward a broad process 

 between the upper and lower processes of the pterygoid. It is quite 

 certain that this was not the case in Ceratosaurus. 



Marsh informs us that there is a very short, thin epipterygoid 

 closely articulated by suture with the pterygoid. The position of the 

 suture is obscure, but it was doubtless present. Marsh was probably 

 mistaken when he affirmed that the upper end of the epipterygoid 



