1883. J NATURAL SCIENCES OP PHILADELPHIA. 105 



of the Dinosauria, which I first announced, as indicated by the hind- 

 limbs, and which Professor Huxley soon after observed in the char- 

 acters of the limbs and pelvis. The confirmation is, however, 

 empirical rather than essential, and is confined to a few points. 

 One of these is the form and position of the vomer, which much 

 reserrbles that seen in lamellirostral birds. The large development 

 of the premaxillary bone has a similar significance. So has the 

 toothless character of that bone and the dentary. 



Among reptiles, this skull combines, in an interesting way, the 

 characters of the two orders Crocodilia and Lace7'tilia. The 

 presence of the ethmoid above the maxillar}- and overlapping the 

 lachrymal, is unique among vertebrata, so far as I am aware. The 

 free exoccipito-intercalare hook is scarcel}^ less remarkable. 



Of mammalian afflnit}^ there is no trace to be found. 



Specific Characters. — The general form and appearance of the 

 skull, as seen in profile, is a good deal like that of a goose. From 

 above it has more the form of a rather short-billed spoonbill 

 (Platalea . For a reptile, the head is unusually elevated poste- 

 riorly, and remarkably contracted at the anterior part of the 

 maxillaries. The flat, transverse expansion of the premaxillaries 

 is absolutely unique. The posterior edges of the occipital bones 

 are produced far backwards, forming a thin roof over the anterior 

 part of the vertebral column. This roof is supported by two 

 strong buttresses, one from each side of the -foramen magnum. 

 The latter is a vertical oval. The exoccipital (carrying the inter- 

 calare) descends on each side, forming a free hook-like process 

 behind the superior half of the quadrate. The recurved process 

 of the lateral branches of the parietal underruns the squamosal 

 two-thirds the length of the latter. The quadrate is separated 

 by a rather narrow, obliquely vertical fossa, from the postorbital 

 arch, owing to the posterior position of the latter. 



The orbit is posterior in position, and is a horizontal oblong in 

 form. The superior (superciliary) border is flat, with slight 

 rugosities at the positions of the pre- and postfrontal sutures. 

 The frontal region is a little concave, and there is a convexity of 

 the superior face of the prefrontal bone in front of the line of the 

 orbit. The peculiar position of the teeth gives the side of the 

 face, when the mandible is closed, a horizontally extended con- 

 cavity. There are four and a half tooth-like colums on each side 

 of the middle line of the end of the muzzle. 



