J. B. Hatcher — Two New Ceratopsia. 419 



Aside from the general proportions of the skull, Dicer atops and 

 Torosaurus differ in the presence in the former of separately ossi- 

 fied epoccipital bones around the margin of the frill. These 

 ossicles are apparently entirely lacking in Torosaurus. The two 

 genera agree in the possession of parietal fenestra though these 

 are evidently not homogenous. They also agree in the form of 

 the postfrontal fontanelle. 



While I believe Diceratops to be a valid genus, I am not 

 inclined to lay the stress upon the parietal and squamosal fenestra 

 which Hatcher does, as they may possibly be pathologic. Those 

 of the squamosal bones, which are found in no other form among 

 Ceratopsia, are not of the same size, while only one is known in 

 the parietals for the sufficient reason that the bone is broken 

 away on the left side where the fenestra would come if present, 

 and it is quite possible that it may never have existed. 



There is preserved in the Museum at Yale University a Clao- 

 saurus scapula with a clean cut foramen through it with perfectly 

 healed edges. This foramen is not present in the other scapula 

 from the same individual and Professor Marsh used to say that 

 the perforation was caused by a Triceratops horn. This certainly 

 seems suggestive of the manner in which the Diceratops fenes- 

 tra may have arisen. Richard S. Lull. 



Amherst, Mass.] 



DESCRIPTION OF PLATES. 



Plate XII. 



Skull of the type specimen of Triceratops brevicomus Hatcher. No. 1834, 

 Yale University Museum. One-sixteenth natural size. 



Figure 1. — Lateral view. ang, angular; art, articular; cp, coronoid 

 process; D, dentary ; ep, epoccipital; ju, jugal ; If, lachrymal foramen; 

 mx, maxillary; no, nasal opening; nh, nasal horn core ; o, orbit; pa, 

 parietal ; pd, predentary ; pmx, premaxillary ; qu, quadrate ; r, rostral 

 bone ; sang, surangular ; sq, squamosal ; soh, supraorbital horn core. 



Figure 2. — Palatal view, clc, dental channel ; exo, exoccipital ; ju, jugal ; 

 mx, maxillary ; pa, parietal ; pal, palatine ; pmx, premaxillary ; pt, 

 pterygoid ; qu, quadrate ; r, rostral bone ; sq, squamosal ; BO, basi- 

 occipital ; C, occipital condyle. 



Plate XIII 



Type skull of Diceratops hatcheri Lull. No. 2412, U. S. National 

 Museum. One-sixteenth natural size. 



Figure 1. — Lateral view, ep, epoccipital ; If, lachrymal foramen ; mt, max- 

 illary teeth ; mx, maxillary; n, nasal; NO, nasal opening; o, orbit; 

 pa, parietal ; pmx, premaxillary ; qu, quadrate ; r, rostral bone ; SF, 

 squamosal fenestra ; soh, supraorbital horn core. 



Figure 2. — Dorsal view, ep, epoccipital; If, lachrymal foramen; n, nasal 

 opening ; o, orbit ; pa, parietal ; paf, parietal fenestra ; pff, postfrontal 

 fontanelle ; r, rostral bone ; SF, squamosal fenestra ; sq, squamosal ; 

 soh, supraorbital horn core. 



