96 THE CERATOPSIA. 



ratojugal notch is deep and the inferior border of the squamosal posterior to this notch is pro- 

 duced downward and forms a rather acute triangular projection. Back of this the external 

 border of the squamosal presents six gentle prominences separated by intervening sinuosities. 

 These are more pronounced and less separated from one another in the anterior region than in 

 the posterior. The border throughout is rather heavy. [See PL XXIII, figs. 1, 3.] 



On its internal and inferior border throughout the posterior one-half of its length the 

 squamosal presents a deep and broad groove for the reception of the slender bone shown by 

 Lambe and seen here in fig. 96. [Also in PI. XXIII, figs. 2, 4.] This bone is imperfect at 

 the posterior extremity, but it is clear that it represents a portion of the external bar of the 

 parietal. Its general form is very similar to that element as seen in the type of Torosaurus 

 gladius Marsh, and it articulates with the squamosal in the same manner. The distal portion 

 of that part of this element preserved in the present specimen presents on its external margin 

 beyond the surface for contact with the squamosal an elongated prominence which, when the 

 bone is placed in its proper position relative to the squamosal, is seen to form a continuation 

 of that series of prominences already described as being present on the border of the squamosal. 

 The internal margin of this external bar of the parietal is very thin throughout most of its 

 length and evidently formed the external border of the parietal fontanelle. I have little hesi- 

 tancy in asserting that the squamosal and frontal horn cores of the present species were 

 associated with a parietal of the same general type as that described by Lambe and referred to 

 Monoclonius belli, and I am of the opinion that the two may be specifically identical, although 

 from the material at hand it is impossible to determine this point with certainty. The supra- 

 orbital horn core and postfrontal found associated with the other remains are similar in form 

 to those which formed the type of Ceratops montanus Marsh and distinct from those associated 

 with the type of Monoclonius crassus Cope. 



The bone figured and described by Lambe (see fig. 96) as a jugal a proves on examination 

 to be a right nasal. It shows posteriorly the proper articular surfaces for contact with the 

 frontals and prefrontals, and sends downward a process for articulation with the ascending 

 branch of the maxillary and premaxillary. Anteriorly it sends downward a process for contact 

 with the premaxillary. Superiorly on its inner surface it presents a broad and elongated 

 articular surface for contact with the opposing nasal. The nasal horn was detached, indicating 

 that the animal was not fully adult. The inferior border is concave and describes a nearly 

 complete semicircle which formed the superior border of the nasal opening. 



In the present species the anterior portion of the squamosal may be described as being 

 composed of a broad vertical portion and a narrower horizontal portion. The horizontal por- 

 tion, together with that of the opposite squamosal, formed most of the superior surface of the 

 skull in this region, reducing the anterior extremity of the parietals to a narrow point, as in 

 Torosaurus. The angle formed by the union of the vertical and horizontal plates at the anterior 

 extremity of the squamosal is produced into a strong ridge and shows a series of rugose promi- 

 nences separated by concave surfaces. One of these latter is very deep. Posterior to these 

 the superior margin of the squamosal is deeply emarginate, and this emargination probably led 

 to the supratemporal fontanelle. 



Monoclonius belli Lambe. 1902. 



Type (No. 491, Geol. Surv. Canada) consists of a parietal. 



Original description, Contr. Canadian Pal., vol. 3 (quarto), pt. 2, 1902, pp. 65-67. 

 Lambe, L. M., Contr. Canadian Pal, vol. 3 (quarto) , pt. 2, 1902, pp. 59, 64, 68, 81. 

 Osborn, H. F., Contr. Canadian Pal., vol. 3 (quarto), pt. 2, 1902, pp. 14, 20. 



The type (No. 491, Geol. Surv. Canada) of the present species consists of the greater portion 

 of the coalesced parietals, as shown in PL XXI. The bone was found by Mr. Lambe in 1898 

 in the Belly River series on the Red Deer River. 



a See footnote, p. 9-1. 



