marsh] CEKATOSAUEUS. 159 



posterior extremity is applied closely to the inner side of the quad- 

 rate. The middle part forms a pocket, into which the lower extremity 

 of the basipterygoid process is inserted. To the lower margin of the 

 pterygoid is united the strong, curved transverse bone which projects 

 downward below the border of the upper jaws, as shown in PI. VIII, 

 fig. 1, t. 



There is a very short, thin columella, which below is closely irnited 

 to the pterygoid by suture, and above fits into a small depression of 

 the postfrontal. 



The palatine bones are well developed, and after joining the ptery- 

 goids extend forward to the union with the vomers. The latter are 

 apparently of moderate size. 



The parasphenoid is well developed and has a long, pointed, anterior 

 extremity. 



The whole palate is remarkably open, and the principal bones com- 

 posing it stand nearly vertical, as in the Sauropoda. 



THE BRALN. 



The brain in Ceratosaurus was of medium size, but comparatively 

 much larger than in the herbivorous dinosaurs. It was quite elongate, 

 and situated somewhat obliquely in the cranium, the posterior end being 

 inclined downward. The position of the brain in the skull, and its rela- 

 tive size, are shown in PL VIII, fig. 3. A side view of the brain cast is 

 shown in PL LXXVII, fig. 2. 



The foramen magnum is small. The cerebellum was of moderate size. 

 The optic lobes were well developed and proportionately larger than the 

 hemispheres. The olfactory lobes were large and expanded. The pitu- 

 itary body appears to have been of good size. 



THE LOWER JAWS. 



The lower jaws of Ceratosaurus are large and powerful, especially in 

 the posterior part. In front the rami are much compressed, and they 

 were joined together by cartilage only, as in all dinosaurs. There is a 

 large foramen in the jaw, similar to that in the crocodile, as shown in 

 PL VIII. fig. 1,/'. The dentary bone extends back to the middle of this 

 foramen. The splenial is large, extending from the foramen forward 

 to the symphysial surface, and forming in this region a border to the 

 upper margin of the dentary. There were fifteen teeth in each ramus, 

 similar in form to those of the upper jaws. 



THE VERTEBR/E. 



The cervical vertebra of Ceratosaurus differ in type from those in 

 all other known reptiles. With the exception of the atlas, which is 

 figured in PL IX, fig. 1, all are strongly cupped on the posterior end of 

 each centrum. In place of an equally developed ball on the anterior 

 end, there is a perfectly fiat surface. The size of the latter is such that 

 it can be inserted only a short distance in the adjoining cup, and this 



