144 BRITISH FOSSIL REPTILES. 



Gavialic modification, not going beyond in the direction of the short and broad-jawed 

 forms, 3'et not quite reduced to the proportions of cranium and face exemplified in 

 the more nearly allied long and narrow-jawed species at present existing in the 

 great rivers of India; Geoffroy's remarks being exemplified by Cuvier's figures, 

 representing the Steneosaurian characters, which I have introduced into PI. 20, 

 (Grocodilia) of the present work. 



Species — Steneosaurus Geoffroyi, Owen, GrocodiUa (PI. 18, fig. 1). 



The mutilated cranial part of a skull (PI. 18, fig. 1), referable to this species, 

 from the Great Oolite of Oxford, shows the following dimensions : 



Inches. Lines. 

 Breadth of hinder or occipito-niastoid surface . . . . . 11 



Height from the lower border of the occipital condyle to the parietal ridge . 4 8 



Length of the temporal fossa . . . . . ..54 



Breadth of ,, ,, ....... 5 



From the intertemporal or parieto-frontal crest the sides slope at once, save at 

 the fore part, where the crest expands to one inch in breadth with a slight superior 

 convexity ; longitudinally the crest is slightly convex. The posterior boundary of the 

 temporal fossa, formed by the parietal and mastoid bones (ib., ib., 7, 8) terminates 

 above in a sharp ridge. The paroccipital (ib. 4) extends from the exoccipital 

 outward to abut against the mastoid. The exoccipitals meet below at their junction 

 with the basioccipital (fig. 2, 1) and exclude it from entering into the formation of 

 the occipital foramen. In Teleosmirus, as in recent Crocodiles, the basioccipital 

 contributes a small share to the lower border of the foramen. Above the suture, 

 extending from the foramen outwards, the exoccipital is perforated by the precon- 

 dyloid foramen, by the entojugular and the entocarotid foramina, the three being 

 in a line extending downward and outward. The cranial canal is relatively smaller 

 than in the Gavial and is subcylindrical. 



So much of the superior maxillary bone (fig. 1, 21) is preserved as shows 

 sockets of 3 teeth in front of, and 27 teeth behind, a short diastema ; there is no 

 groove along the mesial surface of the alveolar part. In the mandible the post- 

 articular angle equals in extent the transverse diameter of the articular surface, 

 approaching thus to pliosaurian proportions, whilst it is longer in the Gavial. 

 The artictdar surface is convex in the middle, concave on each side, not uniformly 

 concave as in the Gavial and modern Crocodiles ; the articular element extends 

 more forward, and is broader on the inner side of the ramus. The depth of the 

 ramus at the coronoid ridge is greater and the ridge itself is higher. There is no 

 vacant interval between the angular and sub-angular elements. 



