no. 1648. 



CERTAIN CARNIVOROUS DINOSAURS— HAY. 



361 



In taking the photographs it has been thought better to remove 

 the lower jaw of the left side, a part of the jugal, the quadratojugal, 

 and the articular end of the quadrate (fig. 2), thereby presenting to 

 better advantage the bones of the palatopterygoid arch. On the 

 right side of the skull (fig. 3) are seen all the bones that bound 

 the orbit, the infratemporal fossa, and the antorbital vacuity. The 

 postfroiito-sqnamosal bar remains. On the left side this is missing. 



On the right side is seen the prefrontal protuberance complete. 

 The anterior half or more of this process is scooped out (fig. 3, in 

 front of 25), the upper part deepest, so that the prefrontal bone is 

 a mere shell. From the hinder border of this excavation a perpen- 

 dicular slit 30 mm. long opens into a cavity that occupies the de- 

 scending process of the prefrontal. On the left side the outer wall 

 of the prefrontal is broken away, so that the matrix filling the cavity 



Fig. 3. — Ceuatosauuus nasicohnis. X I + . Skull seen fkom the eight side. Fob 



EXPLANATION OF NUMERALS, SEE FlG. 2. 



is exposed. In fig. 2 the numeral 25 is placed on the matrix which 

 fills the cavity. The opening into the cavity is in front of the 25. 



On the left side the crowns of three teeth belonging to the lower 

 jaw are seen adhering to the matrix. A large part of the crown of 

 the fourth maxillary tooth, which was pushing itself through the 

 bone, has at some time been exposed by removal of bone. On the 

 right side most of the maxillary teeth are missing. The large tooth 

 lying in the matrix with the apex pointing backward seems, from its 

 narrowness, to be a mandibular tooth. Three mandibular teeth re- 

 main in place. 



It will be observed that there is a large uneven depression in front 

 of and partly above the antorbital vacuity (fig. 2, numeral 14). 

 This is not well shown in Marsh's figure. This depression probably 

 corresponds to the postnarial vacuity figured by Lambe as belonging 



