Animals with scales on their feet, which are held to constitute the earliest stage of the Primate modification of papillary ridges are such as the _potoroo_, _wallaby_, _kangaroo_ and _giant ant-eater_. Such scales register a long, long series of stimuli of friction and pressure in these and their ancestors, in a level of life before any delicate discrimination of surfaces came into operation. The nodular form of skin is present in the Canadian _tree porcupine_, where rough nodules cluster closely on the surface of both feet, and it is a significant fact that it shares with the American _opossum_ the peculiarity of nodules on the ventral surface of the powerful prehensile tail. This adaptation tends to efficiency in its arboreal life, and may well have been produced by infinitely small degrees of response in structure in the course of a long evolution. The _rabbit_ alone have I found with rod-like projections of the epidermic cells, among which are set in dense order the soft, long, delicate hairs and which thus conduce to its wonderful power of treading on sharp objects without injury. We thus see the inner meaning of dear old Brer Rabbit’s jeer of triumph to Brer Fox, “Born and bred in a brier bush.” This adaptation might be an unit-character segregated from the ancestral stock of the Leporidæ, or it might not, but at any rate the rabbit leads a life in which its walking or running is no more prominent or frequent than is a good “run” on the part of a hunter which pursues the hare with his beagles, and one may say at least this--that its mode of life has _not_ produced a hard rough nodular surface on its feet by stimuli of pressure and friction and response. One may observe that there’s a divinity doth shape our ends, rough hew them as we may, even if some objection be taken to the present view of rough-hewing of parts of our organism on the ground of its piecemeal character, rather than dealing with the organism as a whole. To which it may be replied that the Mendelians give high support to the piecemeal study of the profound subject of genetics, and further that the business here is to look separately and simply at a few selected attributes of parts of an organism, and see how they _began_ to grow big enough to avoid passing through the meshes of the sieve. The foregoing examples of animals in which papillary ridges are absent have been given not in their zoological order, nor as representative of a great many groups, but as taken from the eighty-six species I examined myself. The following belong to the same series, but all present papillary ridges in an ascending scale towards perfection in man. Examples of Ridge-covered Palms and Soles.