APPENDIX. 



Art. XIV. — Description of New Dinoeauria/n Reptiles: 

 by O. 0. Marsh. (With Plate I.) 



Recent explorations in the West have resulted in the 

 discovery of many remains of Dinosaurs, some of which are 

 of more than ordinary interest. A few are from the Jurassic, 

 but most of them are from the Cretaceous, especially from the 

 upper portion, in the so-called Laramie formation. Those 

 found in the latter horizon show a high degree of specializa- 

 tion, and present some anatomical features not before observed 

 in this group of reptiles. Several of the new forms are 

 briefly described below, and will be more fully discussed in a 

 later communication. 



Th'iceratops serratas, sp. nov. 



First in importance of the new discoveries is a nearly per- 

 fect skull of the genus Trieeratops, a typical example of which 

 {T. flabeU-atus) was described and figured by the writer in the 

 last number of this Journal.* The present skull is more 

 perfect than any hitherto found, and exhibits admirably the 

 strongly marked characters of the genus. It is likewise of 

 gigantic size, being nearly six feet in length (l*8 m ), although 

 the animal was not fully adult. 



A striking peculiarity of this skull, which has suggested the 

 specific name, is a series of bony projections on the median 

 line of the parietal crest. The latter is elevated along this 

 line to support them, and the sides descend rapidly to their 

 union with the squamosals. There is a second series of ele- 

 vations along the middle of the squamosal bone as it falls 

 away from the base of the horn- core, but these are much less 

 prominent. 



The orbit is nearly circular in form, instead of oval, and is 

 fituated above, and forward of its position in the species re- 

 ferred to. The quadrato-jugal meets the anterior process of 

 the squamosal, forming a closer union than in the skull 

 previously figured. In this respect, and in the elevations on 

 the squamosal, it approaches a much smaller specimen at present 

 referred to the genus Ceratoj>*. 



*This Journal, vol. xxvviii, pp. 501-506, December, 1889. 



Am. Jour. Sci— Third Series, Vol. XXXIX, No. 229.— Jan., 1890. 

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