at some length, and has illustrated by a diagram. The evolution of the horse of historical times, and of the present day from the orohippus of the Eocene period, as exhibited to the eye by Mr. Wallace's diagram, is as interesting a presentation of a physical pedigree as can well be conceived. We see, as it were, the progress of Nature's work; the transformation from several toes to one toe, which was, in reality, the operation of thousands of years, is visible as a connected continuous process from beginning to end. But what the diagram does not, and can not, put in evidence is this—namely, the marvelous beauty of the horse in his ultimate condition. So far as any conclusions can be drawn from the diagram, the top and the bottom of the page stand upon an equal footing; there would seem to be no reason why orohippus should not have been derived from equus by expansion, as easily as equus has been derived from orohippus by contraction. When, however, we look, not at the equus of science, but at the horse of the hunting-field or the race-course, or at our own stable friend, who has carried us safely for hundreds of miles, we perceive that, somehow or other, we have, in these modern days, an animal of the most perfect kind with regard to speed, beauty, and mechanical perfection. We feel convinced that it would be in every way a mistake that he should develop toes and become orohippus; we are sure that orohippus has rightly been improved off the face of the earth in order to make room for equus. All this is, in the best sense of the phrase, in accordance with the principle of the survival of the fittest; but I confess that I find it difficult to realize the transformation of orohippus into equus upon the pure and simple notion of advantageous variations in the struggle for life; for, in truth, if the question be one of mere survival, it is difficult to say, when the earth was inhabited by wild creatures, in what manner the possession of one toe instead of three or four should give equus any advantage over orohippus. One can quite understand that a jury of Newmarket jockeys would decide that equus was fittest to survive; but in the absence of human judgment the conclusion is not so easy to reach. At all events, it seems more probable that the transformation was originally ideally contained in the conception of this class of creature, and that equus may be regarded as bearing to orohippus something of the same kind of relation as is borne by a frog to a tadpole, or by a moth to a caterpillar.
May it not well be that predetermined transformation has as real a place in the genesis of species as it certainly has in that of individual creatures? Nothing, perhaps, strikes most minds as more surprising than insect and reptile transformation. That a crawling animal should, by a complicated process, involving a condition of motionless helplessness, be ultimately transformed into a creature of active life spent in flying through the air, or