MES0Z01C ERA: THE AGE OF REPTILES 



S47 



indicated by the spinose character. It is certainly true that an 

 animal of such bulk, so ornamented, would not be likely to vary to 

 such an extent as to meet radically new conditions. Stegosaurus 

 and its armored ancestors have been found only in the Jurassic. 



Another family of armored dinosaurs, differing widely from Stego- 

 saurus, is represented by Triceratops (Greek, tri-, three, and ceras, horn) 



Fig. 511. — Skeleton of Stegosaurus, an armored herbivorous dinosaur. 

 (After R. S. Lull.) 



(Fig. 513), one of the largest dinosaurs of the time (Cretaceous), with a 

 length of about 20 feet. The noticeable feature of Triceratops is 

 the skull with its two enormous horns, three feet long and six inches 

 in diameter at the base, one above each eye, and a shorter one on the 

 nose. (In a closely related genus the horn on the nose was long while 

 those above the eyes were short.) The skull projected over the neck 

 like a great bony frill and was fringed with short, bony points. The 



