126 



THE CERATOPSIA 



horn so low in the Lance series, as this debars obtusus from the ancestral line of any other species 

 except perhaps T. (Dkeratofs) hatcheri, which occurs two-thirds of the way up from the bottom of 

 the sequence. That it constitutes a valid species is shown by a detached nasal horn of quite similar 

 character in the Peabody Museum collection, No. 1825. This horn is straighter on top and with a 

 less rounded apex when viewed laterally. It cannot be attributed to any other species than this. 



"\ 



\ ,.-■ 



Fig. 41. Left lateral view of skull of Triceratop obtusus, holotype, 1/12 natural size. 



That Triceratop obtusus came from the same general ancestry as Trkeratofs horridus there 

 can be little doubt, although it may represent a distinct line since Edmonton times. Arrhinoceratofs 

 is a structural ancestral possibility, although it presents difficulties, notably in the long squamosal. 



The remaining species of Trkeratofs being "inadequate," I pass at once to a discussion of 

 Dkeratofs, of which the type is ample for description, and also because of its apparent relationship 

 with Trkeratofs obtusus. 



Triceratops (Diceratops) hatcheri Lull 85 



Holotype: 80 No. 2412 U.S.N.M.; skull without the lower jaw. 

 Horizon: Lance formation, No. 11 in the sequence. 

 Locality: Niobrara County, Wyoming. 

 Collector: J. B. Hatcher, 1891. 



This genus and species was described by Hatcher in his incomplete manuscript but left, unfortu- 

 nately, without a name, which had to be supplied by the present author, who edited and completed 

 the first Ceratopsia Monograph. 



85 Lull, R. S., editorial note in Hatcher, J. B., 1905, p. 413. 



86 Hatcher, Marsh, Lull, 1907, Pis. XLVII-XLVI1I. 



