136 EXTINCT MONSTERS 



mouse. Then the sabre-like teeth would be brought into action 

 by the powerful jaws, and soon the flesh and bones of the victim 

 would be gone ! 



As we remarked before, the carnivorous Dinosaurs were the 

 lions and tigers of the Mesozoic era, and, what with small 

 mammals and numerous reptiles of those days, it would seem 

 that they were not limited in their choice of diet. 



During the early part of the Mesozoic era, at the period known 

 as the Triassic (New Red Sandstone), Dinosaurs flourished 

 vigorously in America, developing a great variety of forms and 

 sizes. Although but few of their bones have as yet been dis- 

 covered in those rocks, they have left behind unmistakable 

 evidence of their presence in the well-known footprints and other 

 impressions upon the shores of the waters which they frequented 

 (see p. 48). 



The late Professor Marsh had the good fortune to discover a 

 very peculiar new form of carnivorous Dinosaur, to which he 

 gave the name Ceratosaurus, 1 because its skull supported a 

 horn. But the horn is not the only feature presented by this 

 interesting creature. Its vertebrae are of a strange and un- 

 expected type ; and in the pelvis all the bones are fused together, 

 as in modern birds. Externally, also, the Ceratosaurus differed 

 from other members of the carnivorous group, for its body was 

 partly protected by long plates in the skin, such as crocodiles 

 have : these extended from the back of the head, along the neck, 

 and over the back. An almost complete skeleton was found 

 which indicates an animal about twenty-two feet long. When 

 alive it was probably about half the bulk of the Allosaurus 

 mentioned above. (See Fig. 44.) 



1 Greek keras, horn ; sauros, lizard. Some authorities consider it to be 

 identical with Megalosaurus. 



