7 8 



EXTINCT MONSTERS 



provided. Thus the vertebrse have their " neural spines " 

 expanded at the summit to aid in supporting part of the armour. 

 (See Fig. 62.) The fore limbs were short and massive, but 

 provided with five fingers ; the hind limbs were very much larger 

 and more powerful. These and the powerful tail show that the 

 monster could support itself on them as on a tripod, in an 

 upright position, and this position must have been easily assumed 

 in consequence of the massive hind quarters. As in Iguanodoii, 

 there were three toes to the hind feet, and these were probably 



FIG. 62. Tail vertebrse of Stegosaurus. (After Marsh.) 

 1. Side view. 2. Front view. 



covered by strong hoofs. The fore limbs could move freely in 

 various directions like a human arm, and were probably used in 

 self-defence. (See Fig. 63.) But for this purpose the tail with 

 its four pairs of huge spines would be very effective, and one 

 could easily imagine that a single deadly blow from such a tail 

 would be sufficient to drive away, if not kill, one of the 

 carnivorous enemies of the species. All the plates and spines 

 were, during life, protected by a thick horny covering, which 



