150 THE STORY OF THE EARTH AND MAN. 



oldest animals whicli have a fair claim to be considered 

 reptiles. Still this discovery of old things comes 

 rather of fortune and careful search than of a desire 

 to innovate; and a distinction should be drawn be- 

 tween that kind of novelty which consists in the 

 development of new truths, and that which consists 

 in the invention of new fancies, or the revival of old 

 ones. There is too much of this last at present; and 

 it would be a more promising line of work for our 

 younger naturalists, if they would patiently and 

 honestly question nature, instead of trying to extort 

 astounding revelations by throwing her on the rack 

 of their own imaginations. 



We may pause here a moment to contemplate the 

 greatness of the fact we have been studying — the 

 introduction into our world of the earliest known 

 vertebrate animals which could open their nostrils 

 and literally '^ breathe the breath of life."'^ All pre- 

 vious animals that we know, except a few Devonian 

 insects, had respired in the water by means of gills 

 or similar apparatus. Now we not only have the 

 little land snails, with their imperfect substitutes for 

 lungs, but animals which must have been able to draw 

 in the vital air into capacious chambered lungs, and 

 with this power must have enjoyed a far higher and 

 more active style of vitality; and must have pos- 

 sf'ssed the faculty of uttering truly vocal sounds. 

 What wondrous possibilities unknown to these crea- 

 tures, perhaps only dimly perceived by such rational 

 inteUigences as may have watched the growth of our 



