Note 11 — THE GEOLOGICAL MIDDLE AGE.

The advocates of the development-theory allude to the metamorphosis of animals and plants as supporting their view of a change of one species into another. They compare the passage of a common leaf into the calyx or crown-leaves in plants, or that of a larva into a perfect insect, to the passage of one species into another. The only objection to this argument seems to be, that, whereas Nature daily presents us myriads of examples of the one set of phenomena, showing it to be a norm, not a single instance of the other has ever been known to occur either in the animal or in the vegetable kingdom.