The Bird in the Egg 479 
ably functional. In an embryo chick of even the third 
day this organ is remarkably prominent; but although 
traces of it always remain, yet it fades away to a vestige. 
Look with a hand-lens at the head of a polywog, and 
see the whitish dot between the eyes; or when you touch 
Fic. 370.—Forty-day embryo Ostrich, showing position in the shell. 
the “soft spot” on the head of a human baby, let it recall 
the strange third eye which is its cause. 
And so we might continue to tell of the wonder of 
embryo life: how up to the sixth day the little being 
might be mistaken for the embryo of a reptile or a mammal, 
but from this day onward the bird characteristics become 
more and more noticeable. On the ninth day feathers 
