146 MAURICE G. MEHL 



section just behind the expanded and abruptly downturned tip, 

 the rostrum gradually assumes an A-shaped cross-section. Back 

 from the tip for a distance of about 293 mm. the rostrum does 

 not increase in depth materially. At this point, however, the 

 outhne of the crest bends in a pronounced curve upward for a short 

 distance and then extends in an essentially straight Une up to the 

 anterior border of the nares, 512 mm. from the tip of the rostrum. 

 As the crest approaches the nares after the abrupt rise, it loses 

 much of its angular cross-section. 



The narial 'hump/' while actually rising above the plane of the 

 cranium proper about half an inch and while somewhat accentuated 

 by the depression of the cranial roof in front of the orbits, is not 

 so conspicuous as in several other forms. This is due to the fact 

 that the crest is but sHghtly depressed immediately in front of the 

 nares. 



OPENINGS OF THE SKULL 



The position of the nares is that of the most highly specialized 

 phytosaurs, high on the skull and not far from the eyes. The 

 posterior border of the nares is about 105 mm. in front of the center 

 of the orbit. The openings are 63 mm. long and about 21 mm. 

 wide. They are separated by a moderately thin partition that 

 does not reach the level of the outer borders. The plane of the 

 combined openings is directed upward. 



The orbits are slightly longer than wide, about 62 mm. in 

 diameter. 



The antorhital fenestrae are somewhat distorted. They appear 

 to have been about 104 mm. long and perhaps 45 mm. wide. While 

 they do not extend forward beyond the nares, as is the case in 

 similar forms, this is due to the moderate length of the antorbital 

 fenestrae and not to a unique position. 



The sides of the lateral temporal fenestrae are restored in part. 

 Because of this and some distortion it is not possible to give exact 

 dimensions. It is thought, however, that the greatest diameter 

 was not over 120 mm. 



The supratemporal fenestrae show a development similar to 

 that of Mystriosuchus.^ The posterior border, i.e., the parieto- 



' J. H. McGregor, "The Phytosauria, with Especial Reference to Mystriosuchus 

 and Rhulidodon," Mem. Am. Mus. Nat. Hist., Vol. IX (1906), Part II. 



