12 THE STORY OF REPTILE LIFE. 



The distinctions which enable us so easily to 

 discern the reptile from the amphibian, are 

 based upon observations made upon living ani- 

 mals. A study, however, of the skeletons of the 

 two groups would have led to practically the 

 same results. But supposing there had been no 

 survivors either of the Amphibia or the Eeptiles, 

 then the dividing line would have been very 

 difficult to draw ; for though the skeleton of 

 any of the modern Amphibia differs conspicuously 

 from that of any reptile now living, the same is 

 by no means true of the more primitive types of 

 these two groups. Indeed, even at the present 

 day the greatest experts are not agreed as to the 

 class to which certain very ancient fossils belong. 

 One places them with the Amphibia, regarding 

 them as members of the group known as " Laby- 

 rinthodonts," another with the Keptiles. These 

 creatures, it is not surprising to learn, are ances- 

 tral types from which have probably sprung the 

 living reptiles of to-day. Other and allied forms 

 of the problematical types probably gave rise 

 to some of the fossil species the "Dragons" 

 of the later chapters of this book. Be this as it 

 may, belonging to the same geological era the 

 Permian remains have been found of an un- 

 doubted reptile, known as Palseohatteria, which 

 is represented to-day by an actual living de- 

 scendant, the " Tuatera " of New Zealand. This 

 "living fossil," as it has been called, is thus one 

 of the most remarkable of existing reptiles, and 

 forms in itself a quite distinct group, the fifth, 

 to which reference has just been made. With 

 an ancestry traceable for millions of years, this 



