THE PHYTOSAURIA OF THE TRIAS 147 



ings were probably about the same in both forms. That is, the 

 parietal-squamosal arcades are well devleoped and in the same 

 plane as the dorsal surface of the cranium. The upper posterior 

 border of the lateral temporal fenestra is also wanting. Its width 

 of 80 mm., however, which is greater than that of ^. grandis, would 

 indicate at least an equally large fenestra in A. gracilis. Contrary 

 to what might be expected from this greater width of the lateral 

 temporal fenestra, the bar of bone left between it and the orbit is 

 much more massive than in A . grandis. The orbits are somewhat 

 smaller than in this latter genus, about 45 mm. wide and 75 mm. 

 long. Some 30 mm. below the orbit, in the jugal bar, midway 

 between the lateral temporal fenestra and the antorbital vacuity, 

 is a large, well-defined foramen, probably for the enervation of the 

 powerful cheek muscles as in the modern Gavial. This was not 

 noted, but probably was present in the specimen representing 

 A. grandis. The nares are elevated on a considerable prominence, 

 about 31 mm. above the general level of the roof of the cranium. 

 As in ^ . grandis, they are separated by a thin median partition that 

 does not rise to the same elevation as the posterior and lateral 

 borders of the nares. Thus the nares form, in a way, a common 

 opening about 35 mm. wide and 55 mm. long. The exact length 

 cannot be told, as the anterior borders are weathered away. The 

 state of preservation is such that few of the sutures are distinguish- 

 able. Hence a description of all the separate elements of the skull 

 is impossible. Special attention was paid to the region bordering 

 the nares in the hope that the relations of the septomaxillary bones 

 could be determined. With but a few exceptions the students that 

 have worked with the phytosaurs have overlooked these elements. 

 According to F. von Huene they are present in all of the phytosauria. 

 To quote :'^ "^Vor dem Nasenlocher schliessen die Nasalia nicht 

 zusammen. Hier tritt ein ungewohnlicher Knocken, das Septo- 

 maxillare (bei alien Phytosauriern) dazwischen." 



A diligent search on the specimen representing A. grandis and 

 also Palaeorhinus hransoni failed to show these elements. How- 

 ever, one is forced to conclude that the failure to locate the sutures 

 of such elements is due to the state of preservation of the specimen 



' Op. cit., p. II. The reference is to Belodon {Mystriosuchus) plieningeri. 



