86 



BULLETIN" 110, UNITED STATES NATIONAL MUSEUM. 



directed fore and aft; on the ridge and in front of it they are directed upward . There can be little doubt 

 that the surface behind the ridge belongs to the pterygoid; that in front of it. to the palatine. 



When carefully examined the ascending suture appears to end about 20 mm. below the upper bor- 

 der of the plate of bone of this left side. From this point there appears to be a suture that runs forward 

 some distance. Above this supposed suture the bone fibers are directed forward; below it, near the 

 ridge, they are directed upward; more anteriorly they run upward and forward. The part of the bone 

 with ascending fibers is quite certainly the upper and anterior portion of the palatine. One can not be 

 certain how far forward this bone extends; it seems to reach almost to the front of the antorbital vacuity 



Fig. 54.— (A). Skull op Ceratosaurus nasicornis Marsh. Type No. 4735. U.S.N.M. Seen prom the left side. 

 About $ nat. size. (B), Diagram of the same. Both figures after Hat. 6. Cleft between pterygoids; 7. Den- 

 tary; 8. Epipterygoid; 9. Frontal; 11. Jugal; 12. Lower part of lachrymal; 13. Maxilla; 14. Maxillary depression; 

 15. Nares, external; 16. Nares, internal; 17. Nasal horn; 18. Occipital condyle; 20. Palatine; 21. Parasphenoid; 

 22. Parietal; 24. Postfrontal + postorbital; 25. Lachrymal; 26. Premaxilla'; 28. Pterygoid; 29. Pterygoid process; 

 30. Quadrate; 31. Quadratojugal; 33. Squamosal; 36. Transverse bone; 37. Vomer. 



ending there in a point. It is possible, however, that it ends on the border of the nasal passage about 

 35 mm. behind the front of the antorbital vacuity. 



The bone lying above the palatine and at the front of the antorbital vacuity is undoubtedly the 

 left vomer (fig. 54, numeral 37). This appears to extend backward to meet the pterygoid above the 

 palatine, as drawn in the figure. If this is the case, the palatines did not meet at the midline of the 

 palate. Lambe concluded that in the skull of his Dryptosaurus incrassatus (Albertosaurus sarcophagus 

 Osborn) the palatines were in contact posteriorly. 



