The Reign of Reptiles 



but a few inches broad and high, the largest were 

 about 2 feet in length and depth. Depth is used 

 advisedly, for these plates stood on edge. They 

 were placed far enough apart to permit freedom 

 of motion, and appear to have been arranged 

 alternately and not in pairs. The plates on the 

 upper part of the tail were so small as not to 

 interfere with the use of the tail spines, which 

 were from 1 to 3 feet long, as weapons of 

 offense and defense. And as the stegosaurs 

 were from 15 to 25 feet long, according to 

 age and species, the tail must have been 

 rather formidable. The rest of the body, or at 

 least a portion of it, was protected by small 

 plates, or irregular rounded bits of bone about 

 the size of marbles, embedded in the skin. 

 These, as well as the plates, show that the skin 

 was extremely thick, and altogether the stego- 

 saurs were among the best defended of animals, 

 and the most extraordinary. 



Nearly all the examples of these animals 

 come from Como, Wyo., the exceptions being 

 two closely related species from England. This 

 indicates that the stegosaurs were widely dis- 



171 



