With the exception of whales, we shall find nothing at all resembling cosmopolitanism. Setting aside the whole of Oceania, we only find, as common to both the Old and the New World, two or three ruminants, perhaps a bear, a fox and a wolf. All these species are, moreover, more or less polar, and are wanting in the central regions of the two worlds. Finally, there is not one species of cheiroptera or quadrumana which is indigenous both in America and the Old World. Beyond those species which man has disseminated by making them follow his migrations, animals and plants evidently occupy their natural area, wherein lies the centre from which they have spread. We see that even after this dispersion none of them have acquired an area of habitation which can be compared to that of man. The admission that the human species appeared in every place in which it is found, attributing to it an original cosmopolitanism, would make it a solitary exception in contradiction to the facts presented by all other species. An hypothesis which leads to such a conclusion should be rejected as irreconcilable with the results of observation. If man is now to be found everywhere, it is owing to his intelligence and industry. III. This conclusion is forced even upon polygenists themselves; unless, indeed, they would reject, as inapplicable to man, the laws of zoological and botanical geography. In fact, to whatever extent they may have multiplied their human species, they have been obliged, upon even the slightest study of natural history, to unite them into a single genus. Now, all that has just been said of _species_ applies equally to _genera_. The area of habitation is doubtless increased, and, for example, some genera of cetaceans, as dolphins and rorquals, are found in all seas; and amongst terrestrial mammals, some genera of ruminants and carnivora inhabit, in a greater or less degree, both the Old and the New World. But they are all absent in the greater part of Oceania. Moreover, the higher the types, the fewer is the number of these genera of widely extended areas. Cheiroptera, which are not provided with a nasal membrane, have some genera common to both the Old and the New World. This is no longer the case in cheiroptera, in which the nose is provided with a membrane. There is not a single genus among them, any more than among quadrumana, which inhabits both America and the Old World. Consequently, polygenists must admit that the species of which their _human genus_ is composed could not have come into existence in every place where man is now found, unless they wish to make a striking exception of this _human genus_. IV. Should we wish to regard the human races as forming a _family_ composed of several _genera_, or even as an _order_ comprising several _families_, the same difficulties would present themselves.