Limbs and Pigment-Cells


I NOTICE in a review of Franz's “Geschichte der Organismen” which appeared in NATURE of December 20 a reference to the interesting evolutionary problem of the origin of the limbs of vertebrates. I have no intention of essaying the futile task of endeavouring to influence those whose minds are already made up regarding this problem, but I should like to direct the attention of others to the point that new facts having important bearings upon the problem have come to light in the investigation of the development of these relatively archaic types of vertebrate, Lepidosiren, Protopterus, and Polypterus. A short summary of these facts, and of the conclusions they suggest, will be found in my volume on vertebrate embryology, and the perusal of this summary will, I think, suffice to indicate the grounds for my belief that the older hypotheses referred to by the reviewer will, as knowledge of the relevant facts becomes diffused, be replaced as working hypotheses by the newer view that the limb of the vertebrate has evolved out of a projection from the body-wall which was primitively respiratory in function.

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KERR, J. Limbs and Pigment-Cells. Nature 115, 154 (1925) doi:10.1038/115154a0

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