GENERIC AND SPECIFIC SUMMARY. 173 



The squamosal is somewhat triangular, flat, and moderately thin, the outer edge rounded 

 and wavy in outline. One can not contrast it with those of the other species, for with them the 

 element is unknown. (PL XXIII.) 



( A11 that is preserved of the parietals is a slender bar, triangular in section, which formed the 

 external boundary of the parietal fontanelle. This outer bar is very similar to that of Torosaurus 

 gladius. 



Hatcher says with reference to this species: 



I have little hesitancy 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. 



3. Ceratops {Monoclonius) belli Lambe (pp. 96-97, fig. 98, PL XXI) is founded upon a pair 

 of parietal bones (No. 491, Canadian Geol. Survey). 



The species was described as Monoclonius by Lambe, but was removed to the present genus 

 by Hatcher, for, as he says: 



After a careful study of the type of the present species, together with that of M. canadensis Lambe, one can not avoid 

 being convinced as to their generic identity with Ceratops montanus Marsh, while at the same time the great dissimilarity 

 shown in the parietals and squamosals of these species when compared with the same elements in Monoclonius dawsoni Lambe 

 affords evidence additional to that already pointed out as obtaining in the frontal horn cores, in favor of the generic distinction 

 of the three former species from that of the last-mentioned species. 



The character of these parietals has already been sufficiently discussed, especially since a 

 specific comparison can not be made, as the elements are unknown elsewhere in the genus except 

 for the outer parietal bar of the type of canadensis. 



The material now available affords scant ground for specific distinctions between C. mon- 

 tanus, C. canadensis, and G. belli, and future discoveries may show that these are synonymous. 



INCERTJE SEEIS. 



4. Ceratops {Monoclonius) recurvicornis Cope (pp. 81-87, fig. 90) is based upon fragments of 

 the skull of a young individual (No. 3999, American Museum of Natural History). 



Nasal horn core massive, curving strongty forward, heavier than the supraorbitals and much 

 more compressed distally. The nasal bones narrow rapidly anteriorly, so as to appear wedge 

 shaped when viewed from above. 



The supraorbital horn cores are short, stout, abruptly pointed, and compressed at the sub- 

 triangular apex. The horns are straight, almost erect, in sharp contrast with those of other 

 Ceratops species, and are relatively much smaller, though they show a decided advance over 

 those of Monoclonius. There seems to have been a lesser horn core just in front of the supra- 

 orbital horn, subtriangular in cross section and directed forward. This feature is unknown 

 elsewhere. 



The squamosal is stout-and of considerable size, with no vascular grooves, evidently a juve- 

 nile character, and the edge bears prominences which in turn bear epoccipitals separated by 

 sutures from the squamosal bone. 



This species has been removed by Hatcher from the genus Monoclonius mainly because of 

 the supraorbital horn cores, which resemble those of Ceratops montanus much more than those of 

 Monoclonius crassus. The squamosal is so different from that of the type species M. crassus 

 that, when taken into consideration with the structural differences found in other portions of the 

 skull, especially the horn cores, Hatcher does not hesitate to refer it to the genus Ceratops. 



The presence of separately ossified epoceipital bones in this species, which do not seem to 

 occur elsewhere either in the genus or phylum, together with the size, which is decidedly greater 

 than that of most of its contemporaries, added to the differences between the supraorbital horn 

 cores and those of other members of the genus Ceratops, leads the present writer to doubt the 

 correctness of Hatcher's conclusions in the matter. It should doubtless be removed from Mono- 

 clonius, but it seems rather to represent a new genus in the Triceratops phylum. In the light of 

 our present knowledge, however, this matter can not be settled. 



