Ill Lull, New Name tor the Dinosaurian Limn* Ceratyps. 



Art. X. — A New Name for the Dinosaurian Genus Ct-ratops ; 

 by Ejchard S. Lull. 



In a recent letter to Professor Osborn, Mr. T, D. A. Cocker- 

 ell calls attention to the fact that the name Ceratops, used by 

 Professor Marsh in 1888, for a genus of horned dinosaurs, was" 

 preoccupied by Rafinesque in 1815, who thus designated a 

 genus of birds. 



The dinosaurian genus is a well-defined one from the Judith 

 Piver beds of Montana and their equivalent, the Pelly River 

 of Canada ; the chief generic characters as set forth by J. P. 

 Hatcher* being as follows: "Parietals reduced to a narrow 

 median bar and slender postero-lateral processes, enclosing on 

 either side large elongated parietal fontanelles. External 

 branches of parietals overlapped by the elongated and triangu- 

 lar squamosals. Supraorbital horn cores well developed, 

 circular in cross section except near the base, and curving 

 backward and outward. Nasal horn core strong and curved 

 forward instead of backward as in MonoclonbisP 



The type species is Ceratops montanus Marsh, and Hatcher 

 also included in the genus Monocloniusrecurvicornis Cope, M. 

 canadensis Lambe, and 31. belli Lam be. Ceratops paucidens 

 Marsh, Hatcher abandoned owing to the nature of the type 

 material, which was such as to preclude precise definition. 



This genus is quite distinct from Monoclonius and Centro- 

 saurus, its contemporaries, and 'from the Laramie genera Aga- 

 thaumas, Triceratops, Diceratops and Torosdurus. 



The name Proceratops is offered as a substitute for Cera- 

 tops as suggestive of the latter name and as indicating the fore- 

 runner of the great horned dinosaurs of the Laramie. This 

 necessary change would seem to invalidate Marsh's family 

 name of Ceratopsidse given in 1888 and necessitate the use of 

 Cope's term Agathaumidae (1889) for the group. 



Arnlierst, Mass. 



* Bulletin of the U. S. Geological Survey, No. 257, p. 93. 



