BEING anxious to give the reader a sample of the arguments against the theory of natural selection from among variations that are mainly either directly or indirectly functional in their inception, or more briefly against the Erasmus-Darwinian and Lamarckian systems, I can find nothing more to the point, or more recent, than Professor Ray Lankester’s letter to the _Athenæum_ of March 29, 1884, to the latter part of which, however, I need alone call attention. Professor Ray Lankester says:— “And then we are introduced to the discredited speculations of Lamarck, which have found a worthy advocate in Mr. Butler, as really solid contributions to the discovery of the _veræ causæ_ of variation! A much more important attempt to do something for Lamarck’s hypothesis, of the transmission to offspring of structural peculiarities acquired by the parents, was recently made by an able and experienced naturalist, Professor Semper of Wurzburg. His book on ‘Animal Life,’ &c., is published in the ‘International Scientific Series.’ Professor Semper adduces an immense number and variety of cases of structural change in animals and plants brought about in the individual by adaptation (during its individual life-history) to new conditions. Some of these are very marked changes, such as the loss of its horny coat in the gizzard of a pigeon fed on meat; _but in no single instance could Professor Semper show_—although it was his object and desire to do so if possible—that such change was transmitted from parent to offspring. Lamarckism looks all very well on paper, but, as Professor Semper’s book shows, when put to the test of observation and experiment it collapses absolutely.” I should have thought it would have been enough if it had collapsed without the “absolutely,” but Professor Ray Lankester does not like doing things by halves. Few will be taken in by the foregoing quotation, except those who do not greatly care whether they are taken in or not; but to save trouble to readers who may have neither Lamarck nor Professor Semper at hand, I will put the case as follows:—