Prof. 0. C. Marsh — Restoration of Triceratops. 249 



available for examination makes it possible to attempt a restoration 

 of one characteristic form, and the result is given in Plate VII. 

 This figure, about one-fortieth of natural size, is reduced from a 

 large outline plate of a memoir on this group, now in preparation by 

 the writer for the United States Geological Survey. 



This restoration is mainly based on two specimens. One of these 

 is the type of Triceratops prorsus, Marsh, in which the skull, lower 

 jaw, and cervical vertebrae are in remarkable preservation. The 

 other specimen, although somewhat larger, is referred to the same 

 species. It consists of parts of the skull, of vertebra, the pelvic 

 arch, and nearly all the important limb bones. The remaining 

 portions are mostly taken from other remains found in the same 

 horizon and localities, and at present are not to be distinguished 

 specifically from the two specimens above mentioned. The skull as 

 here represented corresponds in scale to the skeleton of the larger 

 individual. 



In this restoration, the animal is represented as walking, and the 

 enormous head is in a position adapted to that motion. The massive 

 fore limbs, proportionally the largest in any known Dinosaur, 

 correspond to the head, and indicate slow locomotion on all four feet. 



The skull is, of course, without its strong horny covering on 

 the beak, horn-cores, and posterior crest, and hence appears much 

 smaller than in life. The neck seems short, but the first six 

 cervical vertebras are entirely concealed by the crest of the skull, 

 which in its complete armature would extend over one or two 

 vertebrae more. The posterior dorsals with their double-headed ribs 

 continue back to the sacrum itself, there being no true lumbars, 

 although two vertebree, apparently once lumbars, are now sacrals, as 

 their transverse processes meet the ilia, and their centra are coossified 

 with the true sacrum. The four original sacral vertebrse have their 

 neural spines fused into a single plate, while the posterior sacrals, 

 once caudals, have separate spines directed backward. 



No attempt is made, in this restoration, to represent the dermal 

 armour of the body, although in life the latter was more or less 

 protected. Various spines, bosses, and plates, indicating such dermal 

 armature, have been found with remains of this group, but the 

 exact position of these specimens can, at present, be only a matter 

 of conjecture. 



This restoration gives a correct idea of the general proportions 

 of the entire skeleton in the genus Triceratops. The size, in life, 

 would be about twenty-five feet in length, and ten feet in height. 

 The genus Ceratops so far as at present known is represented by 

 individuals of smaller size, and in some instances, at least, of quite 

 different proportions. A third genus, which may be called Ster- 

 rholophus, can be readily distinguished from the other two by the 

 parietal crest, which had its entire posterior surface covered with 

 the ligaments and muscles supporting the head. In Ceratops and 

 Ticeratops, a wide margin of this surface was free, and protected by 

 a thick, horny covering. The type of the new genus is the specimen 

 described and figured by the writer, as Triceratops flabellatus, which 



