104 



THE CERATOPSIA 



determined above the free border but posteriorly it is well denned. The extreme anterior border is 

 concave and the angle formed by the two borders is produced into a sharp process followed by the 



epoccipital bones. 



"The epoccipital bones are one of the most striking features of the skull. They are extensive, 

 covering the margin of the crest completely, all firmly coossified to the underlying bone but with 

 sutural union distinct. On the squamosal there are six, the anterior five about equal in size, the sixth 

 very much larger. . . . Following these on each side are three epoccipitals equally of enormous size. 

 They are attached to the border of the postfrontals ('parietals') and directed backward and outward. 

 The surface is slightly roughened and they taper from the thick elongate base to the rounded point 

 and thin borders. 



"Immediately above the base of the last epoccipital is a pair of massive, short, curved processes 

 suturally united to each other and in the type specimen not distinct from the postfrontals below. 

 In the skull of the young specimen, No. 5273, however, one of these processes was taken off and 

 found to be united by suture to the supporting bone. They are large and curve outward ending in 

 short blunt points. They differ slightly in form and position from the hook-like processes of Mono- 

 clones [Centrosaurus] but, as in that genus, probably served as attachment for muscles and were 

 not sheathed in horn" [see, however, p. 35]. 



Brown compares Anchiceratops with Styracosaurus albertensis, from the Belly River of Alberta, 

 which he says "resembles Anchiceratops in some respects and may have been its ancestor. In both 

 the crest is comparatively flat with [ep?] occipital bones unusually developed but in this later form 

 the squamosals are progressively lengthened, the lateral fontanelles are reduced and the ex [ep?] 

 occipitals are shortened. The development of the supraorbital horns is also distinctive." 



The fragmentary crest of Styracosaurus ovatus Gilmore, from the Two Medicine formation of 

 Montana, with its further shortened epoccipital spines, is still more like the posterior part of the 

 crest of Anchiceratops. 



When one sees the entire skull of Anchiceratops, as in the type specimen of A. longirostris 

 Sternberg, the resemblance to Styracosaurus is less marked, especially in the forward region of the 

 skull. For the face and muzzle of Anchiceratops are elongated more as in Chasmosaurus, and the 

 nasal horn is low, projects forward, and has a sharp dorsal edge, very different from the long, nearly 

 erect horn of Styracosaurus. 



Anchiceratops longirostris Sternberg 52 



PI. X 



Holotype: No. 8535 G.S.C.; nearly complete skull, without lower jaws. 



Horizon: Edmonton formation. 



Locality: 12 miles northwest of Morrin, Red Deer River, Alberta, from approximately the same locality as 



A. ornatus. 

 Collector: C. M. Sternberg, 1924. 



Sternberg's description adds the following points, some of which, like the very long and slender 

 nose, may be specific rather than generic characters. For instance, though the same type of muzzle 

 ordinarily prevails in Chasmosaurus, yet there is at least one skull of the genus (No. 5436 Ct. 

 R.O.M. PI. VII, A), preserved at Toronto, in which the muzzle is shorter and deeper than usual. 

 And so it may have been with Anchiceratops where, in the only known specimen in which the anterior 

 part of the skull is preserved, the latter is long and slender, yet it may have varied, specifically, to 

 a shorter, deeper, muzzle correlated with a shorter, wider, crest. 



"Viewed from the side, . . . [PI. X, A] the skull [of A. longirostris] is very long and flat, the 

 orbit is well in advance of the midline; the anterior naris is long and situated nearer to the orbit 

 than to the end of the beak. . . . The rostral bone resembles that of Chasmosaurus and as in that 

 genus the beak is made up largely of the premaxillae. . . . 



52 Sternberg, C. M„ 1929. 



