300 THE TRANSFORMATIONS OF THE ANIMAL WORLD 







More frequently still we may note between the 

 two regions the presence of representative, but not 

 identical genera, showing that similar groups 

 followed their evolution on parallel lines, but inde- 

 pendently of each other. Thus in the primitive 

 Crocodilians of the Trias, the Belodon of Wurtem- 

 burg is represented by the Episcoposaurus of New 

 Mexico. The curious Aetosaurus of Stuttgart, 

 with its slender snout and back adorned with rows 

 of oblique plates, is represented by the Typoihorax 

 of the United States. In the group of carnivorous 

 Dinosaurs, the Zanclodontidce of the European 

 Trias offer a parallel development to that cf the 

 American Anchisauridce. The genus Ccelurm, a 

 type of the family of the light and agile Cseluridse, 

 is represented in Europe by the Aristosuchus of the 

 Isle of Wight. Among the clumsy Sauropods, the 

 gigantic Atlantosaurus of the Colorado upper 

 Jurassic is fairly near to the Oxford Cetiosaurus, 

 and the American Morosaurus is represented by the 

 Ornithopsis of the English Wealdian. Finally, the 

 great horned Dinosaurs of the group of Ceratop- 

 sidce, which imitate so singularly the carriage of the 

 Rhinoceros and are so brilliantly represented in the 

 higher Cretacean of the Rocky Mountains by the 

 Ceratops and the Triceratops, count among their 

 members, in Europe, closely similar forms in the 

 Struihiosaurus, and the Danubiosaurus of the horizon 

 of Gosan, in the Neue Welt, near Vienna. 



Notwithstanding this geographical individualiza- 

 tion, already marked in the Trias and still more so 

 in the Jurassic and Cretacean, a certain number 

 of palaeontological facts favour partial migrations 



