182 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—archeopteryx—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 annals, utterly insignificant in 
