408 Di. C. W. Aiulrews on the 



tlie alveolar border. From this point these sutures run 

 first obliquely upwards and backwards, tiieu backwards 

 parallel to one another, and forming the outer borders of 

 the transversely arched and greatly elongated facial pro- 

 cesses of the preiuaxillie, which extend far back behind the 

 external nares to the broken end of the fragment. They 

 are divided by a median suture. 



The alveolar border of the maxilla is broadly convex in 

 its anterior portion, then beneath the point of tl»e orliit it 

 becomes concave, behind which it is nearly straight, ex- 

 tending some distance behind the orbits. The external 

 nasal opening is about opposite the middle of the convex 

 portion of the maxilla, and much further in front of the 

 orbits than in Rhomaleosaurus cramptuni : the distance 

 between these openings and the tip of the snout is about 

 31 cm.; probably the nasals and prefrontals took part in 

 the formation of their borders, but the crushing undergone 

 by the specimen renders this region obscure. The ventral 

 border of the orbit is formed anteriorly by the maxilla and 

 posteriorly by the jugal. At its hinder end the inner 

 border of the maxilla joins a massive bone with a strong 

 downwardly directed tuberosity ; this is the transpalatine, 

 and probably a portion of the pterygoid is united with it. 

 Anteriorly this bone and the maxillary are separated by a 

 notch with a rounded border, presumably the posterior 

 edge of a suborbital vacuity. 



The middle of the palatal surface of the anterior expan- 

 sion of the snout is occupied by a forward extension of the 

 vomers, Avhich nearly reach the alveolar border, and are 

 bounded by ridges on the prernaxillte. Behind this the 

 vomers widen out, first joining the maxilla; and then 

 separating the internal nares by a broad, transversely 

 convex bar of bone : the posterior end of these openings is 

 about opposite the hinder wall of the alveolus of the fourth 

 maxillary tooth. Behind the nares the vomers widen out, 

 and, no doubt, united with the anteiior ends of the ptery- 

 goids : probably the palatines extended between these latter 

 and the maxillie, extending forwards to reach the narial 

 openings, but the sutures are here obscure. 



The first premaxillary tooth is small and close to the 

 middle line, then come three greatly enlarged teeth, and, 

 lastly, just in front of the maxillo-premaxillary suture a 

 smaller one. The first tooth in the maxilla is also small, 

 then come five very large ones, occupying the convex 

 portion of the alveolar border : behind tiiese there is a 

 series of about fourteen smaller teeth, diminishing in size 



