THE "OSTRICH" DINOSAUR AND THE "TYRANT' DINOSAUR 13 



cestral form, the "bird catcher" of 

 Jurassic time, OrnWiolestes. 



Thus the theories of several expert 

 anatomists who have cooperated with 

 the author in attempting to solve the 

 riddle of this "ostrich mimic" indicate 

 very great diversity of opinion and of 



less, descended from similar ancestors: 

 Tyrannosmirus extremely large-headed, 

 with powerful teeth, very short neck, 

 and short, powerfully clawed fore limbs 

 and enormous hind limbs provided with 

 very powerful recurved claws ; Struthio- 

 niimus extremelv small-headed, the 



The "Ostrich Mimic" Dinosaur, Struthiomimus, and the "Tyrant" Dinosaur, Tyrannosaurus. — To il- 

 lustrate the wide contrasts between the skeleton of the "ostrich mimic" dinosaur (right upper) and that of 

 the "tyrant" dinosaur (left lower), animals which, notwithstanding their extreme unlikeness in adaptation 

 to habits, descended from similar ancestors. Photographed to the same scale 



interpretation. It is agreed only, first, 

 that the animal was a very swift run- 

 ner, and, secondly, that it was in all 

 probability herbivorous and that per- 

 haps the hand was adapted for search- 

 ing out and grasping some particular 

 form of shrub or fruit. 



The contrast which this animal pre- 

 sents to Tyrannosaurus gives us one of 

 the greatest extremes known to science 

 of two types adapted to most widely 

 different habits which have, neverthe- 



toothless jaws sheathed in horn, the 

 neck elongated and highly flexible, 

 neither the fore nor the hind limbs 

 adapted for seizing a live prey. In both 

 animals the hind limbs are adapted to 

 very rapid progression. In the case of 

 Tyrannosaurus this is designed to over- 

 take the prey, while in Struthiomimus 

 this length of limb was doubtless to 

 enable the animal to escape from ene- 

 mies, among which may have been the 

 Tyrannosaurus itself. 



