306 Dr. C. W. Andrews on some new Steneosaurs 



Mandible. 



Total lengtli _ 85 



Len^ith of sympliysial region 37 '5 



Width at hinder end of symphysis 10-2 



„ at narrowest point behind anterior expansion. 3'8 



Steneosaurus ohtusidens, sp. n. (PI. IX. fig. 2.) 



One of the rao't important of the skeleton.s collected by 

 ]\Ir. Leeds is that of a very large and massively built crocodile, 

 of wliicli we possess the skull, niandiljle, numerous vertebrae 

 and ribs, some bones of both the pectoral and pelvic girdles and 

 of the fore and hind limbs, together with some scutes. These 

 specimens (R. 3168) are the types of the present species. 



The skull differs from that of the other Steneosaurs in 

 having a thicker and more massive rostrum and teeth with 

 tliick blunt-pointed crowns. As in the last species, the 

 temporal fossaj are very large and about twice as long as 

 broad. The orbits are large and oval. The frontals seem to 

 have terminated anteriorly in a blunt point about on a level 

 with the front border of the orbit ; their surface is orna- 

 mented by a number of obscure ridges radiating from the 

 centre of the united bones. Tiie arrangement of the nasals 

 and lachrymals cannot be made out, owing to the crushing 

 that that region has undergone. There was a small slit-like 

 antorbital foramen, about 7 cm. in front of the orbit. In 

 front of the orbits the rostrum narrows very gently to a point 

 about 16 cm. behind its anterior end, where it is only 6"2 cm. 

 wide; the premaxillary region is expanded and the facial 

 processes of the premaxillEe terminate posteriorly in a blunt 

 point. The nasal opening is transversely oval, the anterior 

 border being interrupted by a prominence occurring at the 

 point of union of the two bones. The rostrum, as a whole, 

 is stout and its upper surface is strongly arched from side to 

 side; the anterior end seems to have been bent a little up- 

 wards. The total number of teeth in the upper jaw cannot 

 be made out, but it can be seen that in the premaxilla there 

 were four, of which the two anterior are small and crowded 

 together, so that the second is almost behind the first. The 

 third and fourth are much enlarged. 



In this skull the length of the preorbital region is about 

 61 per cent, of the whole ; in S. leedsi and S. nasutus the 

 proportion is about I'd per cent. ; but in S. durobrivensis it is 

 much the same as in the present species, which, however, 

 differs in the more gradual narrowing of the rostrum. 



