88 THE CERATOPSIA 



part of the frill. Postfrontal fontanelle large. Supratemporal fossae opening widely behind. 

 Nasal horn-core large, upright, straight, rising from the back of the nasals. Supraorbital horn-core 

 incipient." 



This is the most bizarre of all the ceratopsian genera, one in which the spines and processes 

 borne on the skull have run riot. The holotype of S. albertensis is preserved at Ottawa, and consists 

 of a splendid skull without the lower jaw, although an artificial mandible has been taken from 

 another genus and modified to fit. The skull is entire, except for the following: part of the rostral 

 bone, a little more than the distal half of the nasal horn core, and portions of the spines bordering the 

 parietal part of the crest. There is no reason to suppose that these restorations are other than 

 correct, as they continue the contour of the elements to which they are attached. 



The nasal horn core is heavy, with an elliptical cross-section and, as preserved, there is no 

 trace of axial curvature either forward or backward. It is not quite erect, however, but inclines 

 slightly forward. As with Monoclonius including Centrosaurus, the horn is slightly constricted at 

 the base before the vascular impressions begin. The anterior margin of the horn lies just over the 

 posterior limit of the nares as in Chasmosaurus, hence it lies relatively farther back than in 

 Monoclonius, wherein the middle of the horn core overlies the posterior margin of the nares. The 

 nasal extends but little behind the horn. 



The supraorbital horns were incipient, and the actual ossifications were apparently lost during 

 maceration, for a distinct but irregular facet is visible over the rear margin of each orbit. A second 

 specimen, mentioned by Lambe, shows the same condition. The premaxillaries are broadened out 

 below, but are deeply depressed and smooth in the narial area. The length and comparative shal- 

 lowness of the muzzle recall Chasmosaurus rather than Monoclonius. The posterior limit of the 

 premaxillary is far removed from the lacrymal. This was found to be a variable condition in 

 Monoclonius. The vestigial preorbital fossa (lacrymal foramen) lies, therefore, between the nasal 

 and maxillary only. 



The jugal is deep, and not very extensive fore and aft. There is no indication of an epijugal. 

 The squamosal is short, as in Monoclonius, and bears five crenulations, but no separate epoccipitals. 

 The fused parietals form the bulk of the crest. The sutures between them and the frontals and post- 

 frontals are clearly defined on either side of and within the postfrontal fontanelle. 21 



The orbit is broadly elliptical, the longitudinal axis lying upward and slightly backward, about 

 45° out of the perpendicular. The crest bears three pairs of large spike-like prominences and three 

 pairs of small ones. There are some faint vascular impressions on the surface of the crest itself, but 

 they are many and deep on the processes. The posterior pair of large processes is divergent and 

 slightly curved outward; they are not, however, complete throughout their entire length, so this is 

 conjectural. The intermediate pair is straight and also diverges outward, but they are more perfect, 

 especially as the tip of the left one is preserved, so that there is little doubt of their correct restora- 

 tion. The forward pair, which again is slightly curved outward, underlies the intermediate pair a 

 little, at their base. Here, again, there is some restoration, but it is evidently correct. Of the small 

 prominences, the hinder pair, which arises on the superior surface of the crest, is suggestive in posi- 

 tion of the forwardly projecting processes on the crest of Monoclonius {Centrosaurus), while the pair 

 on the lateral margins of the crest, just in front of the anterior large processes, is like those of 

 Monoclonius {Centrosaurus) in character but not in position, in that they show the same grooved or 

 fluted surface. In front of these processes on either parietal margin are two other prominences com- 

 parable to and probably homologous with epoccipitals, although again without sutural limitation. 

 Viewed from above, the crest gives the impression of having been pulled away from the frontal area 

 of the skull at the posterior limit of the fontanelle. There is, however, no evidence of fracture. It 

 gives the entire skull, when viewed from the side, a flattened aspect unlike any other ceratopsian 

 except Torosaurus gladius as restored (see PL XVI). As Lambe says, 22 "In lateral aspect the skull 

 is depressed and very long in contrast with its height. The spike-shaped processes double the length 



21 Sternberg, C. M., 1927, A, p. 140. 

 "Lambe, L. M., 1913, p. 110. 



