84 ANIMALS OF THE PAST 



quite small, in some places, particularly in the sacral 

 region, it is subject to considerable enlargement. This 

 is notably true of Stegosaurus, where the sacral en- 

 largement is twenty times the bulk of the puny brain — a 

 fact noted by Professor Marsh, and seized upon by the 

 newspapers, which announced that he had discovered a 

 Dinosaur with a brain in its pelvis. 



Skulls or Tkicbratops and Teachodon 

 Illustrating the small size of the brains, shown in black. The brains of 

 these animals, twice thebulkof an elephant, were the size of a man's fist. 



In their great variety of size and shape the Dinosaurs 

 form an interesting parallel with the Marsupials of 

 Australia. For just as these are, as it were, an epitome 

 of the class of mammals, mimicking the herbivores, car- 

 nivores, rodents and even monkeys, so there are carniv- 

 orous and herbivorous Dinosaurs — Dinosaurs that 



