BINOSA URS. 
Ill 
remains from several localities. The most striking feature — from 
which the Stegosaur takes its name — was the presence of huge 
bony plates belonging to its skin, as well as large and small 
spines. Some of the plates were from two to three feet in diameter, 
and they were of various shapes. Of the spines, some were of 
great size and power, one pair being each over two feet long ! 
The skull was remarkably small, and more like that of a lizard 
than we find in most Dinosaurs ; the jaws were short and 
massive. Little was known at first of the brain, but fortunately 
a later discovery showed the brain-case well preserved. Later 
still, more than twenty other specimens of this Dinosaur were 
obtained, so that nearly every portion of the skeleton is now 
known. The skulls indicate that the creature possessed large eyes 
and a considerable power of smell. The jaws contain but a 
single row of teeth in actual use ; but as these wore out, they 
were replaced by others lodged in a cavity below. Teeth, how- 
ever, were not its strong point ; they indicate a diet of soft 
succulent vegetation. The vertebrae have the faces of their 
centra more or less bi-concave. Many curious features in the 
skeleton can only be explained with reference to the heavy 
armour of plates and spines with which the Stegosaur was 
provided. Thus the vertebrae have their “ neural spines " 
expanded at the summit to aid in supporting part of the armour. 
(See Fig. 26.) The fore limbs were short and massive, but pro- 
vided 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 posi- 
tion, and this position must have been easily assumed in conse- 
quence of the massive hind quarters. As in Iguanodon, there 
were three toes to the hind feet, and these were probably 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. 27.) But for this purpose the tail with its 
four pairs of huge spines would be very effective, and one could 
