O. C. Marsh—The Order Theropoda. 333 
THe BRAIN. 
THe Lower JAWS. 
The lower jaws of Ceratosawrus 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 Plate VIII, figure 
1, f. The dentary bone extends back to the middle of thi 
foramen. The sihietal 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. 
A J culiar dentary bone, recently found, and here referred 
to Labrosaurus, is shown on Plate LX, figure 4. It is edent- 
lous in front, and the posterior portion is much decurved. 
The teeth are more triangular than in the other hanes of 
an order. The species it represents may be called Labrosaure 
THE VERTEBRA. 
The cervical vertebree of Ceratosaurus differ in type from 
those in any other known Reptiles. With the exception of 
the atlas, whi 
