Insects and birds, on account of the vast number of species they present, furnish the best available material for the study of evolution. It is owing to the fact that most Professors of Zoology are neither entomologists nor ornithologists that biological science is in its present deplorably backward condition. There exists scarcely a zoological theory, be it neo-Lamarckian or neo-Darwinian, that the competent ornithologist is not able to refute. For example, writing of sexual dimorphism in animals, Cunningham states that in the case of birds which exhibit such dimorphism the cocks differ essentially in habits from the hens, and in this way he, as a Lamarckian, would account for their external differences. “The cocks of common fowls and of the _Phasianidæ_ generally,” he writes, “are polygamous, fight with each other for the possession of females, and take no part in incubation or care of the young, and they differ from the hens in their enlarged brilliant plumage, spurs on the legs, and combs, wattles, or other excrescences on the head. In the _Columbidæ_, _per contra_, the males are not polygamous, but pair for life, the males do not fight, and share equally with the females in parental duties. Corresponding with the contrast of sexual habits is the contrast of sexual dimorphism, which is virtually absent in the _Columbidæ_.”
Mr. Cunningham evidently is not acquainted with the red turtle dove (_Œnopopelia tranqebarica_) so common in India, or he would not have asserted that sexual dimorphism is virtually absent in the _Columbidæ_. The sexes in this species are very different in appearance, and I know of nothing peculiar in its habits to explain this dissimilarity. The sexual dimorphism displayed by the red turtle dove is a fact equally awkward for the Wallaceians, because the habits of this species appear to be in no way different from those of the other doves. I have seen red turtle doves feeding in company with the three other common species of Indian dove; they eat the same kind of food, build the same ramshackle nests, and lay the usual white eggs. But I will not spend time in whipping a dying horse. The poor overburdened beast which we call Natural Selection has done yeoman service; for years he has pulled the great car of Zoology along the rugged road of knowledge, and now that he is past work, now that he stands tugging impotently at the traces, it is time to pension him and replace him by a new steed. Unfortunately, the drivers of the coach happen to be old gentlemen, so old that they fail to perceive that the coach is at a standstill. They believe that they are still travelling along as merrily as they were in Darwin’s time. Ere long their seats will be occupied by new drivers, who will give the good steed Natural Selection a well-earned rest, and replace him by a fresh animal called Mutation. Then once again the coach will resume its journey.