l82 THE MEANING OF EVOLUTION 



in a manner not unlike that of the flying squirrel of 

 to-day. Among these experimenters in aviation, cer- 

 tain forms produced scales which became elongated 

 and finally slit up along the side. These slit scales 

 slowly developed into the feathers of the birds of 

 to-day. Whether the steps by which the change oc- 

 curred have been correctly stated or not, the result 

 is sure. In the rocks of the chalk period we find the 

 remains of an interesting creature. If nothing but its 

 bones had been found it would have been called a 

 reptile. It had a long tail, it had claws on its front 

 limbs; it had teeth in its mouth; it had a flexible 

 backbone. All of these are reptilian rather than bird 

 characters. Yet on the rocks surrounding these bones 

 are the unmistakable impressions of the feathers of 

 the wings and of the tail. Nothing in the world to- 

 day has feathers excepting the birds, and in this "an- 

 cient winged thing," for this is the significance of its 

 name archseopteryx we have perhaps the most re- 

 markable link in the world between two distinct sec- 

 tions of the animal kingdom. Here is a creature half 

 reptile, half bird; perhaps one-third reptile and two- 

 thirds bird. It was about the size of the crow. A 

 little later unmistakable bird skeletons will appear, but 

 still their jaws are provided with long conical teeth. 

 Still more interesting from our standpoint is an- 

 other set of primitive animals, utterly insignificant in 



