Lamarek versus Weismann

Abstract

MR. WALLACE'S note with the above title in NATURE (vol. xl. p. 619) contains an illustration of a kind of reasoning that is so common with the post-Darwinians (I know of no other concise expression to designate this class of thinkers) that I desire to call attention to it. His remarks are àpropos of the twist in the skull of the flat-fishes, and of Dr. Lankester's comments on the explanation of its origin offered in his book “Darwinism.” Mr. Wallace has, as it appears to me justly, ascribed the rotation of the eye of these fishes to the “transmission of a series of slight shiftings of the eye acquired in successive generations by the muscular effort of the ancestors of our present flat-fish” (Lankester, in NATURE, vol. xl. p. 568). This, observes Lankester, pointedly, is “flat Lamarckism.” Now Mr. Wallace explains that he has added the following language, which he thinks negatives the explanation cited by Dr. Lankester; “those usually surviving whose eyes retained more and more of the position into which the young fish tried to twist them.” Mr. Wallace then says that the “survival of favourable variations is even here the real cause at work.”