It is scarcely fair to ask for space to answer his momentous challenge about the first vertebrate, or to explain the thoroughly sceptical form which the challenge assumes. When the Apostle Thomas said, ‘except I see the print of the nails, I will not believe,’ he had no logical claim to receive the proof of the resurrection which he demanded, because _a priori_ it would have been quite fair to suppose our Lord’s resurrection-body would retain no such signs of previous outrage; and it is a kindred mistake to suppose that the truth of the development-theory in any way hinges upon the possibility of constructing an effigy of the first vertebrate either as it actually was, or to suit an anti-Darwinian’s notions of what it ought to have been. According to the development-theory, it must have been the product of innumerable antecedent factors, itself the heir of many far-descended and often modified characters; and yet, for all that, it will probably have been a far simpler organism than the simplest modern vertebrate. It is well known by what insensible gradations the natural kingdoms and the classes in those great divisions pass, so to speak, into one another; it need, therefore, cause no surprise if the primary vertebrate of all the vertebrates should prove neither to have been fish, flesh, fowl, nor good red herring; but for an actual specimen of a living vertebrate that can neither ‘swim, crawl, fly, nor walk,’ I cannot do better than refer my philosophical opponent to a new-born baby. THE FIRST VERTEBRATE, AND THE BEGINNING OF REASON.