Page:Popular Science Monthly Volume 33.djvu/841

 earth, is brought into active operation. Great rivers spring from the melting fields of snow and ice that crown the mountain-summits, and, swollen by the copious condensation of rain on their slopes, flow down to the plains below, which are fertilized by their perennial waters.



UR lectures hitherto have shown us that science has not yet succeeded in casting a clear light on the exact connections of the placental mammalia, and that it is still ignorant of the precise ways, direct or indirect, by which the present orders and families have been derived. Haeckel's genealogy has been the point of departure for numerous essays, which have rendered immense services; but, as the author himself declares, it is only a first sketch, and will have to be revised hereafter. It has been shown by our lectures that the present orders, families, and genera are the product of a long evolution and successive transformations, and did not exist when the first placental mammalia appeared, and when the first feebly determinative evolutionary movement of differentiation and reduplication of types, which led to existing forms, was manifested in the marsupials. It is also shown that the progressive passage from the marsupial fauna of that time to the existing fauna did not take place by a single series of species for each order, family, or genus, but in all the cases in which science is in possession of sufficient documents, by multiple series, anastomosing, intercrossing one another, and often constituting an inextricable network.

Here and there the advance seems to have been more direct, as in the ungulates, the carnivores, the cheiroptereschiroptera [sic], and the pinnipeds or aquatic carnivora, while in other orders, such as the insectivora and the rodents, it seems to have been in an exceedingly complicated way. That branch which, according to Haeckel, leads to man, is the one that interests us most. Let us consider, then, the station which succeeds that of the marsupials, the eighteenth from the moneres in Haeckel's genealogy, the lemurs.

The lemurs have been ranked among the quadrumana by Geoffroy Saint-Hilaire, Cuvier, De Blainville, Duvernoy and Milne-Edwards—that is, separated from man; and among the primates, or in the same order with man, by Linnæus, Lesson, Huxley, and Broca. Vogt and Haeckel call them prosimians, the Germans half-apes, and the French sometimes false apes. The dominant question in our investigation is, therefore, where they belong: 