ANCIENT SALAMANDERS 89 
I 
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 
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. 
ganoid fishes, which also possess 
similarly infolded teeth. Again, 
. 15. — Magnified section of tooth of 
Labyrinthodont. (After Owen.) 
