OEETACEOUS VEETEBEATE FOSSILS. 515 



of the fourth vertebra is free, and the remaining cervicals are of the same 

 general form, ;i]| having their articular faces nearly flat. 



The anterior dorsal vertebrae have very short centra, with flat articular 

 ends, and resemble somewhat those of Stegosaurus, especially in the 

 neural arch. 



The posterior trunk vertebras have also short, flal centra. 



The sacrum was strengthened by the union of several vertebrae, ten 

 being coossified in one specimen of Triceratops. The middle or true 

 sacral vertebrae have double transverse processes, diapophyses being pres- 

 ent, and aiding in supporting the ilium. This character has been seen hith- 

 erto in the Dinosauria onhj in Ceratosaurus and some other Theropoda, 



Besides the armature of the skull the body, also, in the Ceratopsidae 

 was protected. The nature and position of the defensive part- in the 

 different forms can not yet be determined with certainty, but various 

 spines, bosses, and plates have been found that clearly pertain to the 

 dermal covering of Triceratops or nearly allied genera. Several of these 

 ossifications were probably placed on the back, behind the cresi of the 

 skull, and some of the smaller ones may have defended the throat, as in 

 Stegosaurus. N 



In the restoration on PI. XX VI I the animal is represented as walking*, 

 and the enormous ht/ad is in a position adapted to that motion. The mas- 

 sive tore limbs, proportionally the largest in any known dinosaur, corre- 

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



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

 horh-cores, and posterior crest, and hence appeal-- much -mailer than in lite. 

 The neck seems short, hut the first six cervical vertebrae are entirely con- 

 cealed by the crest of the skull, which in its complete armature would 

 extend over one or two vertebrae more. 



No attempt is made in this restoration t< i represent the dermal armor 

 of the body, although in life the latter was more or less protected. Various 

 ossifications indicating such dermal armature have been found with remains 

 of this group, but the- exact position of these specimens can he, ;it present, 

 only a matter of conjecture. 



