422 0. C. Marsh — New Cretaceous Dinosaurs. 



New Cretaceous Dinosaurs. 

 Triceratops sulcatus, sp. no v. 



One of the largest skulls of Triceratops secured during the 

 past season was not in good preservation, although nearly the 

 whole was recovered, and with it various vertebrae and other 

 portions of the skeleton. The animal was fully adult, as 

 shown by the ossification of the epoccipital and epijugal bones 

 with the portions of the skull on which they rest. The epi- 

 jugal bones are especially prominent and rugose, and the 

 sutures uniting them with the jugals are nearly obliterated. 



The most distinctive character of the skull is seen in the 

 horn-cores of the frontal region, which are very large and 

 elongate. On the posterior surface of the upper half of each 

 horn-core, there is a deep groove, which has suggested the 

 specific name. The horn-cores are narrow in front, and in 

 the upper portion become distinctly ridged. 



The antero-posterior diameter of the horn-cores at the base 

 is about nine inches, and above, where the groove begins, 

 about four and a half inches. 



The caudal vertebrae in this species are unusually short, and 

 the median caudals have a deep, longitudinal groove on the 

 bottom of the centra. 



Thi& type specimen was found in the Ceratops beds, in 

 Wyoming, by Mr. J. B. Hatcher. 



Trachodon longiceps^ sp. no v. 



In the same horizon with the Oeratopsidce, remains of other 

 gigantic Dinosaurs are found, but as yet only detached portions 

 of the skull and skeleton have been secured. One of the 

 largest of these specimens is a right dentary bone, nearly per- 

 fect, which surpasses in size the corresponding part of any of 

 the Ceratopsidce hitherto found. This dentary bone is fairly 

 well preserved, and now measures over thirty-eight inches in 

 length. When complete, it must have been fully three and 

 one-half feet long. The front part, extending back eighteen 

 inches, is edentulous. The alveolar portion is of equal length, 

 and the border shows depressions for fifty-one teeth in a con- 

 tinuous series. These teeth had only a single root, and in 

 general form, resemble those of Hadrosaurus. On the buter 

 side of this dentary bone, there is a strong, rounded ridge, ex- 

 tending from the base of the coronoid process to the front, as 

 now preserved. The dentary bone, as a whole, is slender, quite 

 unlike any hitherto described, and represents a well-marked 

 species. 



The type specimen of the present species was found by Mr. 

 J. B. Hatcher, in the Laramie of Wyoming. 



