JURASSIC PERIOD 91 



selves in condition, these enormous vegetarians must have 

 spent the greater part of their Uves in eating. 



Whilst some dinosaurs were chiefly remarkable for their 

 colossal proportions, others were signalised rather by their 

 grotesque appearance. Look at Stegosaurus, for instance, 

 with his pikes and battlements. His dorsal castellation, no 

 doubt, denied him the luxury of rolling on his back ; but it 

 kept him well guarded against assault in that quarter. A 

 number of Uttle bones well shielded his throat ; whilst his 

 flanks, though somewhat exposed, could doubtless be covered 

 by a sweep of the spiky tail. The mere sight of such animals, 

 standing in some cases eleven feet at the highest point of their 

 fortifications, must have inspired some terror. They certainly 

 required elaborate protection, for they were bulky, heavy- 

 limbed, and incapable of speedy flight. Nor were they Hke 

 Diplodocus, capable of taking a wide survey, and catching 

 early sight of danger. As they were vegetarians in diet, they 

 were probably, in spite of grim aspect, peacefully enough 

 disposed when unmolested. 



Their intelligence must have been very limited ; for their 

 brains were excessively small, even for dinosaurs. Curiously 

 enough a mass of nervous tissue — ^the result probably of a 

 block caused by the smallness of the brain chamber — was 

 lodged in the region of the haunches. It has been suggested 

 that this second accumulation was in the nature of a supple- 

 mentary brain — that it formed, in short, a second seat of 

 intelligence. No doubt the " upper chamber " was of 

 extraordinarily mean capacity ; and, in the interests of 

 good government, some check on its prerogatives may have 

 been desirable ; but there is really no reason to suppose that 

 the " lower chamber " contained any intelligence at all. 



The Stegosaurus genus was confined to North America ; 

 but remains of distantly allied forms have been found in 

 England (Scelidosaurus). These animals were capable of pro- 

 gression, in a somewhat laboured style, without requisitioning 

 the " arms " ; and the tail no doubt served as a useful 

 appendage on which to take short rests. They possessed 

 well-developed shoulder-spikes ; but they were not so elabor- 

 ately armed as Stegosaurs. 



