XI 



adapted for grinding up large quantities of vegetable 

 matter. The deep compressed tail indicates that it may 

 have been used for swimming, and that the animal frequented 

 lakes or marshes, and perhaps escaped its enemies by 

 taking to the water. It appears to have had no protective 

 armour. 



Another group is named Stegosauria, " plated lizards," 

 from their protective armour. The skeleton of one of 

 these (Fig. 53) has long bony spines on the shoulders, 

 which, if bearing a horny covering, would have been an 

 effective protection against beasts of prey ; and this is 

 followed by a row of bony knobs on the sides, which also 

 probably carried spines protecting the vital organs. A row 

 of similar bones along each side of the powerful tail may 

 also indicate spines, which would have rendered this an 

 effective weapon against an enemy from the rear. 



FIG. 54. SKULL OF HORNED DINOSAUR (Sterrolophus flalellatus). 

 From the Upper Cretaceous of Wyoming, U.S.A. (B.M. Guide.) 



In another allied species, of which the skull is here 

 shown (Fig. 54), there were two enormous horns above the 

 eyes and a smaller one upon the nose ; while the margin 

 of the bony expansion behind seems to have borne a row of 

 spiny plates. 



