276 



CAPT. D. M. S. WATSON ON SEYMOURIA, 



surangular ; the inner, more faintly marked depressions for the 

 prearticular and angular. The posterior surface bears a minute 

 knob representing the postarticular process. 



Dentary. — In general the sutures on the outer surface of the 

 jaw are not well shown. The dentary, however, forms the entire 

 outer surface for some distance behind the symphysis, posteriorly 

 it ends in a point which is received in a groove in the surangular. 

 Fragments belonging to the young individual show that it carried 

 a single series of rather large round teeth. Its admesial surface 

 has a long perfectly straight suture with the coronoids. 



Splenial. — The splenial appears to enter the symphysis. It 

 forms the lower border of the anterior portion of the jaw, its 

 suture with the dentary running along just above the lower edge 

 on the outer surface. The greater part of the bone, however, 

 forms a flat inner surface articulating above with the first and 

 second coronoids, and behind with the prearticular and pre- 

 angular. 



Preangular. — The preangular is a channel-shaped bone forming 

 the lower part of the jaw, articulating above with the dentary 

 on the outer surface and the prearticular on the inner, with the 

 splenial in front and the angular behind. 



Angular. — The angular is only very incompletely preserved, 

 but is a bone of the ordinary reptilian pattern. 



Prearticular. — The prearticular is a very large bone running 

 from the articular to the splenial. Its lower edge has long 

 sutures with the angular and preangular, interrupted so as to 

 leave an anterior internal mandibular vacuity between the pre- 

 articular and preangular and a posterior vacuity bounded by 

 prearticular and angular. 



Coronoids. — The fracture referred to above shows that there 

 are three coronoids forming together a continuous strip wedged 

 in between the dentary and surangular on the outside and the 

 prearticular and splenial within. 



The 1st or anterior bone is small and incompletely exposed, it 

 is not shown to bear any teeth . 



The 2nd is of considerable size, and in the middle of its length, 

 which in life lies immediately outside the palatine tusks, is 

 thickened and carries a tightly packed mass of small granular 

 teeth . 



The 3rd, posterior, coronoid forms the anterior border of the 

 supra-meckelian vacuity, extending back along the sides of that 

 opening in contact with the inner surface of the surangular 

 outside and the upper edge of the prearticular below. This 3rd 

 coronoid bears one large bluntly pointed tusk at about the middle 

 of its length : this tooth is oval in cross-section and was appa- 

 rently received in a special pit in the ectopterygoid. 



Vertebral Column. 



Atlas. — The first vertebra preserved in my skeleton is the 

 atlas. The parts preserved are slightly displaced. 



