LET me remind the readers of NATURE that the discussion which has been going on in these columns, between the Duke of Argyll and Mr. Thiselton Dyer, arose out of a reference in Mr. Wallace's book on “Darwinism” to the dislocation of the eyes of flat-fishes. Two views have been expressed as to the origin of this arrangement—the one endeavouring to explain it as a case in which a “sport” or congenital variation, had been selected and intensified; the other attributing it to the direct action of the muscles of ancestral flat-fishes which had pulled the eye out of its normal position, the dislocation thus established being transmitted to offspring, and its amount increased by like action in each succeeding generation. In common with Mr. Wallace and other naturalists, I spoke of this latter hypothesis as one of transmission of an “acquired character.” The term “acquired character” was clearly enough defined by this example; it has been used in England for some years, and its equivalent in German (erworbene Eigenschaften) has been defined and used for the purpose of indicating the changes in a parent referred to by Lamarck in the following words (“Philosophie Zoologique,” tome i. p. 235, edition Savy, 1873):—