128 



THE CEEATOPSIA. 



a considerable portion of the skeleton (Burwell specimen) of a species of the Trachodontid.se 

 was found. 



In several subsequent papers Professor Marsh referred material from other localities to 

 the present species, thereby furnishing additional specific characters. Of first importance 

 among such supplementary material was a considerable portion of the skeleton of a single 

 individual, now in the collection of the U. S. National Museum (No. 4842). a The remains of 

 this skeleton, which included several vertebra? and ribs, the sacrum, pelvis, scapula, represen- 

 tations of all the limb bones except the radius and fibula, several foot bones, a portion of a 

 horn core, etc., were found by me at the place marked + sk. c. in PI. LI. The locality is 

 near the head and on the north side of a small draw (not shown on the map) which empties 

 into Lance Creek from the east, about lh miles below the U-L ranch. About 100 yards 

 above the point where the skeleton was found is a small cottonwood grove by a spring, near 



which my party camped while engaged in tak- 

 ing up the bones. In dry seasons, however, 

 this spring ceases to flow. The horizon is a 

 ledge of sandstone at about the same level, I 

 should judge, as that which furnished the type 

 of Triceratops horridus, and I should judge it 

 to be considerably lower than that from which 

 the skull that forms the type of the present 

 species was obtained. In view of the probable 

 difference in the horizons at which the two 

 specimens were found, and the fact that a frag- 

 ment of a supraorbital horn core is all that the 

 two specimens have in common for direct com- 

 parison, as well as the fact that this more 

 nearly resembles the same element in the type 

 of T. elatus, as will be seen by a comparison 

 of fig. 108 and PI. XLIII, their specific iden- 

 tity can hardly be considered as demonstrated 

 or as even being capable of demonstration, and 

 I prefer to limit the definition of the present 

 species to the type specimen, which may now 

 be described in detail. 



DETAILED DESCRIPTION OF THE TYPE SPECIMEN. 



The type (No. 1822, Yale Museum) consists 



Fig. 108. — Right supraorbital horn core found with skeleton (No. „ , , . r -, . ., , , .., 



4842, U. S. National Museum) referred by Marsh to Tricera- of the SIX [seven] anterior Cervical vertebrge, With 



tops prorsus. It resembles more nearly the same element in ^he skull and lower jaWS Complete, Save the SUm- 



T. elatus. Compare with PI. XLIII. One-eighth natural size. » . , ■> ». , ., -, , -. . , 



mit of the left supraorbital horn core and the 

 median posterior portion of the parietal, which had weathered away and were lost before the 

 specimen was discovered. The parts recovered indicate that the animal was fully adult and 

 perhaps in advanced old age when it met death. Most of the cranial sutures are closed. 

 The epoccipitals and epijugals are firmly coossified with their respective elements, while the 

 entire external surface of the skull is rugose and marked with a multitude of deep vascular 

 impressions or canals, especially conspicuous on the squamosals and parietals, where they 

 present a labyrinth of ramifying branches, most of which converge about and lead into the 

 large supratemporal fossae. 



The present species, which includes nearly the smallest if not the very smallest representa- 

 tives of the family known from the Laramie formation, is readily distinguished by the following 

 characters: (1) The long and anteriorly directed nasal horn core; (2) the slender supraorbital 

 horn cores directed upward, forward, and outward throughout about one-half their length, 

 when they begin and continue to curve gently inward from thence to the summit; (3) the 



a This is the mounted skeleton. See pages 189-192; fig. 124; PI. XLIX.— R. S. L. 



