The Ancestry of the Marsupialia

IN the notice (NATURE, December 24, 1908) of Prof. A. A. W. Hubrecht's paper on the early ontogeny of the Mammalia, the writer states that the view adopted by Prof. Hubrecht, according to which the Metatheria are the descendants of placental ancestors, is in direct opposition to my own. May I be permitted to correct this statement, and to point out that it is just this view which I have all along advocated, and still hold? As a matter of fact, the idea that the Metatheria and Eutheria may best be regarded as the divergent branches of an ancestral placental stock was first definitely expressed in a joint paper by Prof. J. T. Wilson and myself (Quart. Journ. Micros. Sc., vol. xxxix., p. 579).