APPENDIX. 



Art. XXI. — Notice of Gigantic Horned Dinosauria from 

 the Cretaceous ; by Professor O. C. Marsh. 



The remarkable reptiles which the writer recently described, 

 and placed in a new family, the Ceratopsidce* prove to be 

 more and more wonderful as additional specimens are brought 

 to light. There appear to be two or three genera, and several 

 well-marked species, already discovered, and the object of the 

 present paper is to notice briefly some of their characteristic 

 features so far as investigated. 



Triceratops horridus, gen. nov. 



The animal described by the writer as Ceratops horridus^ 

 possesses some remarkable characters not before known in the 

 Dinosauria. In addition to the pair of massive horn-cores on 

 the top of the skull, there is a third horn-core on the nose. 

 This is median, as in the Rhinoceros, and is placed on the end 

 of the nasals, which are firmly coossified to support it. 



The edentulous premaxillaries are compressed anteriorly, and 

 are strongly coossified with each other and with a third bone in 

 front, which corresponds to the pre-dentary bone below, the 

 whole forming a projecting beak, like that of a tortoise. Over 

 all, there was, evidently, a huge horny covering, like the beak 

 of a bird. 



The bone in front of the premaxillaries has apparently not 

 before been observed in any vertebrate, and may be called the 

 rostral bone (os rostrale). It is analogous to the pre-nasal 

 ossification of the pig, and of the Dinocerata. 



Other portions of the skull show features not before seen 

 in the Dinosauria. There is a huge occipital crest, extending 

 backward and outward. In the present specimen, this is bent 

 downward at the sides, like the back part of a helmet, thus 

 affording, in life, strong protection to the neck. 



* This Journal, vol. xxxvi, p. 417, December, 1888. 

 f Ibid., vol. xxxvii, p. 334, April, 1889. 

 Am. Jour. Scl— Third Series, Vol XXXVIII, No. 224.— August, 1889. 

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