THE PHYTOSAURIA OF THE TRIAS 139 



Jaekel/ a little larger, however, and more slitlike. In both of 

 these forms the post-palatine foramina are considerably larger than 

 in most of the other phytosaurs. The inter-pterygoid vacuity is 

 notable in this form for its antero-posterior extent, being about 

 103 mm. long. It gradually diminishes in width from 35 mm., its 

 greatest lateral extent, near its posterior boundary, to a very acute 

 angle about 30 mm. back of the posterior border of the nares. 



THE SEPARATE BONES OE THE PALATE 



The posterior extension of the premaxilla is indeterminate; 

 apparently it lacks quite a little of reaching the anterior border of 

 the nares. 



The vomers seem to have little lateral extent. The exact con- 

 dition cannot be seen, however, as none of the boundaries is dis- 

 tinguishable. In all probability they unite broadly in front with 

 the premaxillae and form most of the anterior border of the nares as 

 well as their median borders. They probably do not extend as far 

 back as the posterior end of the nares, certainly they cannot extend 

 any considerable distance beyond. 



Apparently the maxillae do not enter the nares at all. This is 

 a condition suggested by Lees in Palaeorhinus hransoni {op. cit.. 

 Fig. 2). If they do take part in the boundaries of these openings 

 it is very slight and along the antero-lateral borders. The pterygo- 

 palatine sutures are also more or less hypothetical. 



The palatines reach far forward, forming most or all of the lateral 

 borders of the nares. They seem to join the pterygoids posteriorly 

 about the middle of the posterior palatine foramina. At the 

 anterior ends of these openings they connect very slightly with the 

 transverse (ectopterygoid) bones, if at all. On the general plane of 

 the palate their greatest width is about 52 mm. along a line con- 

 necting the anterior ends of the posterior palatine foramina. At 

 this width they are bent almost vertically upward in an antero- 

 posterior direction. 



The pterygoid hones form the walls and roof of most of the 

 spacious palate arch back of the nares. Only a small triangular 



' "tJber einen neuen Belodonten aus dem Buntsandstein von Bernburg," Sit- 

 zungsherichten der Gesellschaft naturforschender Freimde, No. 5, Jahrgang, 1910, p. 209, 

 Fig. 5- 



