46 THE STORY OF REPTILE LIFE. 



mention, but compels us to omit much that 

 we would have said about the species which we 

 have selected for discussion. 



CHAPTER IE. 



CROCODILES. 



FEROCIOUS and repulsive in appearance, the 

 Crocodiles of to-day nevertheless are a most 

 interesting and highly important group. To 

 them belongs the distinction of being at once the 

 largest as well as the most highly organised 

 of all the Irving Reptiles. 



Their origin is still a mystery. The earliest 

 known members of the group carry us back to 

 the Liassic period ; but previous to this there 

 had existed in the still older Keuper formations 

 crocodilian forms which, though more primitive 

 in structure in some respects, were yet too 

 specialised in others to render it possible to 

 regard them as the ancestors of the Crocodiles 

 of the Lias and their living descendants. That 

 the Crocodiles, in a wide sense, that is, includ- 

 ing the very early forms of the Keuper forma- 

 tions are related on the one hand to the 

 remarkable Tuatera Lizard (Hatteria), and on 

 the other to the still more remarkable and 

 extinct Dinosaurs, there can be no doubt. 

 More remotely the group appears to be related 

 to the Tortoises and the extinct Plesiosauria, 

 the long-necked fish-lizards of the Trias and Lias. 



