386 THE PORTLAND OOLITE PERIOD. CHAP. 



The temporal fossae are large and oval, contracted toward the 

 orbits. The frontal bone extends into a long prominence between 

 the nasals, having on each side elongate pre-frontals. At the 

 juncture of the anterior parts of these with the nasals is a deep 

 groove or canal, corresponding in place to the nasal foramina of 

 enaliosaurs (Cuv., Ossemens Foss. Plate VIII. fig. 8 d). 



The frontal shews three parts, and was probably composed of 

 five, but the limits are hardly traceable. 



The maxillary bone is not known. The under surface of the 

 frontal and pre-frontal bones is scooped in hollows corresponding 

 to the general figure of the bones, which are about half an inch 

 thick. A part of the brain cavity is exposed on the under side 

 of the specimen. 



In the lower jaw a thin, nearly vertical plate of bone (the 

 'surangular') extends from the articulation forward, and rises into 

 a prominent coronoid process, as far in front of the condyle as 

 the articular bone extends backward. The concave articular surface 

 is directed forward and downward. The lower or ' angular' element 

 of the inner jaw is inflected inwards. 



The following are some of the dimensions of the head and lower 

 jaw : 



inches. 



Lower jaw. Length from the end of the articular bone to the posterior 



edge of the articular surface . . . . . . . .2-1 



Length to the anterior edge . 2-9 



Length to the crest of the surangular bone . . . . . . 6'o 



Height of the jaw at the surangular crest 2-8 



Cranium. Extreme breadth over the jugal bones 8-25 



Breadth of occipital surface from condyle to condyle . . . . 6*75 



Extreme height of occipital surface 4'75 



Breadth of occipital condyle . . . . . . . . 1*20 



Height of the same .......... O'8o 



Diameter of foramen magnum . . . . . . . *75 



i 



Vertebrae. The axis corresponds in general to that in the cro- 

 codile (see Cuv., Ossemens Fossiles, iv. 3), shewing like it a short 

 posterior neural crest, with the zygapophyses plane, oval, and 

 inclined about 160. In the anterior and lower part is the odontoid 

 bone, separated by a clear suture from the corpus. One styliform 

 process proceeded from the odontoid, and another from the body 

 of the axis immediately behind it. 



