154 



THE CERATOPSIA. 



The last of these four prominences forms the antero-inferior angle of the squamosal and marks 

 the posterior border of the quadratojugal notch, which is much shallower than in other genera 

 of Ceratopsia. The groove for the quadrate is far in advance of the position which it occupies 

 in other o-enera. The more important characters of the squamosal are well shown in fig. 14,1. 



The supratemporal fossse, were deep and elongate and the floor of each appears to have been 

 stronger than in Oeratops or Triceratops. As in the type species of the genus, there was a small 

 foramen on either side of the parietal just within the anterior lateral borders of these fossse. 

 From these foramina two broad, shallow channels run forward along the superior surface of 

 the parietal. These converge and meet in the median line at the anterior extremity of the 

 parietals, where there seems to have been a single median postfrontal (pineal) foramen instead 

 of two placed one on either side of the median line, as inthe preceding species of this genus. 



Fig. 119.— Dorsal aspect of skull of typa of Torosaurus gladius Marsh (No. 1831, Yale Museum), c, Supratemporal fossa; e', epijugal bone; 

 /', parietal fontanelle; h, supraorbital horn core; h', nasal horn core; p, parietal; s, squamosal; x, postfrontal foramen. One-twentieth 

 natural size. After Marsh. 



Owing to the imperfect condition of the specimen in this region, it is not possible to determine 

 with accuracy whether there were one or two of these foramina. 



Taken as a whole the entire frill, notwithstanding its great size, which considerably exceeds 

 that of any member of the Ceratopsia yet discovered, was remarkably light and frail and could 

 have formed but a very inefficient protection to the cervical region. The surfaces of the bone 

 are throughout smooth and entirely devoid of those grooves, channels, and rugosities so char- 

 acteristic of the parietals and squamosals in the genus Triceratops. In the present specimen 

 the entire frill seems to have been embedded in or covered \>j soft, muscular tissue instead of 

 bearing a thick and dense dermal or horny sheath, as would appear to have been the case in 

 Triceratops and fully adult specimens of Sterrholophus. 



Only one of the supraorbital horn cores is preserved and a portion of the base of this is 

 wanting. It shows these horn cores to have been rather long, slender, and somewhat com- 

 pressed transversely, with a very rugose surface deeply furrowed with vascular groves, indi- 

 cating that in life they were covered with formidable horns. They were directed forward, 

 upward, and outward, and, assuming that the facial region was correspondingly as short in 

 the present as in the preceding species considering their length, they must have extended 

 nearly or quite as far forward as the nasal horn. 



The nasal horn core, which was found detached, is very short and stout, compressed, and 

 has a very sharp-pointed apex. Its surface is extremely rugose and shows a number of deep 

 vascular grooves for the protection of the blood vessels which lay between the bone and the 

 heavy horn with winch in life it was insheathed. The surface of this horn core is broadly 



