THE "GENERAL MORPHOLOGY" 223 



to man himself must also have done so. Hence 

 the law must have transmitted even to ourselves 

 this ancestral form of the gill-breathing fish. 



What a mad idea, many will say; that man 



should at one time be a tadpole like the frog! 



And yet — there's no help in prayer, as Falstaff 



gaid — even the human germ or embryo passes 



through a stage in the womb at which it shows 



the outline of gills on the throat just like a fish. 



It is the same with the dog, the horse, the 



kangaroo, the duck-mole, the bird, the crocodile, 



the turtle, the lizard; they all have the same 



structure. Nor is this an isolated fact. From the 



fish was evolved the amphibian; from this came 



the lizard; from the lizard, on Darwinian principles, 



the bird. The lizard has solid teeth in its mouth ; 



the bird has no teeth in its beak. That is to say, 



it has none to-day ; but it had when it was a 



lizard. Here, then, we have an intermediate 



stage between the fish and the bird. We must 



expect that the bird-embryo in the egg will show 



some trace of it. As a matter of fact it does so. 



[When we examine young parrots in the egg we 



[find that they have teeth in their mouths before 



i the bill is formed. When the fact was first 



discovered, the real intermediate form between the 



lizard and the bird was not known. It was 



afterwards discovered at Solenhofen in a fossil 



impression from the Jurassic period. This was 



the archeopteryx, which had feathers like a real 



bird, and yet had teeth in its mouth like the lizard 



when it lived on earth. The instance is instructive 



