Let us now fancy that we are looking upon one of these strange little elongated globes, and that instead of being _opaque_, that is, dark--not clear, it is transparent, so that we can see into it, and observe the changes which are taking place there. The mother bird has been sitting on it for, say twelve hours, and the warmth of her body has called into action the principle of growth, or of vitality; the little spot and ring in the centre of the yolk have become somewhat enlarged and changed in form; they are no longer round, but the outline is irregular, shewing a tendency to shoot or spread out on all sides. Four hours later shews them yet more enlarged, and getting into an oval shape, with a distinct, though somewhat broken line down the centre. When the _incubation_ has lasted thirty-six hours, (for meaning of this word, see the first series of "Nests and Eggs,") there is a still greater increase in the germ, and a spreading of its mottled margin over a portion of the yolk; if at this stage of growth we examine it through a magnifying glass, we shall see a little body like some curious kind of caterpillar, and veins shaped like stags' horns branching out of it in every direction. On the fourth day the chick is a more strange-looking object still, with great projecting eyes with rings round them, like spectacles, and what appears to be a very blunt sort of a snout or muzzle; the whole head, and there is not much else, reminds one of that of a serpent, it might be the Cobra di Capello, or the Spectacle Snake, seen through a diminishing glass. But we cannot give a proper description of it, so we have called in the aid of our artist, who has furnished us, on the next page, with portraits of the interesting creature at four different stages of its growth. In the last we get a side view, and begin to fancy we discover some resemblance to a baby-fowl, although a very hideous one. [Illustration: 36 hours. 4 days. 6 days. 10 days.]