2. “That often, in adjacent islands, we find animals closely resembling and appearing to represent each other; while, if certain of these islands show signs of more ancient separation, the animals inhabiting them exhibit a corresponding divergence. 3. That “‘rudimentary structures’ also receive an explanation by means of this theory. 4. “That the singular facts of ‘homology’ are capable of a similar explanation.” 5. That “that remarkable series of changes which animals undergo before they attain their adult condition, which is called their process of development, and during which they more or less closely resemble other animals during the early stages of the same process, has also great light thrown on it from the same source.” 6. That “by this theory, and as yet by this alone, can any explanation be given of that extraordinary phenomenon which is metaphorically termed ‘mimicry.’” To explain in detail the exact import of each of these heads would carry us beyond the limits of a magazine article; and the reader who wishes for more minute and definite information on them we must refer to Mivart’s own book, or to Darwin’s _Origin of Species_. Pass we now to those facts which Darwin’s theory is incompetent to explain, and to the arguments against it. Mr. Mivart enumerates them thus: 1. “That ‘natural’ selection is incompetent to account for the incipient stages of useful structures. 2. “That it does not harmonize with the coexistence of closely similar structures of diverse origin. 3. “That there are grounds for thinking that specific differences may be developed suddenly instead of gradually. 4. “That the opinion that species have definite though very different limits to their variability is still tenable. 5. “That certain fossil transitional forms are absent which might have been expected to be present. 6. “That some facts of geographical distribution supplement other difficulties. 7. “That the objection drawn from the physiological difference between ‘species’ and ‘races’ still exists unrefuted.” Our readers will readily understand that, if species, or rather individual animals, were originated by natural law, and if that law be “natural selection,” the action of “natural selection” must be able to explain not only the production of the animal as a whole, but of its several organs, both when they have reached the point of maximum utility, and at all stages previous thereto.