ANCIENT SALAMANDERS 



89 



peculiarity. They are the Labyrinth-toothed amphibians (see 

 Fig. 15). 



At first sight it might perhaps seem to the uninitiated as if 

 the internal and minute structure of a tooth were a matter of 

 comparative unimportance ; but it is recognised by all anato- 

 mists that teeth are highly important as indicating the place 

 of an animal in the scale of being. In the present case, for 

 instance, the possession of teeth 

 with the labyrinthine structure 

 indicates an affinity with certain 

 ganoid fishes, which also possess 

 similarly infolded teeth. Again, 

 there is a peculiarly low type 

 of reptiles, known as the 

 Ichthyosaurus, or " fish-lizard," 

 of which the teeth show an 

 approach to the same kind of 

 structure. Some of the Laby- 

 rinthodonts retained the gills 

 of their youth through life, 

 instead of changing them for lungs, as frogs do. 



But, if these facts tend to connect the Labyrinthodonts with 

 fishes below, there are others which tend to connect them with the 

 reptiles above. Sir Eichard Owen, by a bold piece of reasoning, 

 arrived at the conclusion that certain huge and somewhat frog-like 

 skulls, previously discovered in German Triassic rocks, belonged 

 to Labyrinthodonts. This was an important step ; but then the 

 question arose, What kind of creature made the tracks found in 

 these strata, both in Germany and England ? This question 

 cannot be answered with any certainty, as we have stated on p. 41 . 

 But we know that Anomodont reptiles and Dinosaurs abounded. 



Labyrinthodont. (After Owen.) 



