[231] The Mexican _Axolotl_, the _Triton Alpestris_, and probably others. [232] _Nature_, March 24, 1892. [233] i.e. the Science of Causes. [234] _Dictionnaire encyclopédique des sciences médicales._ [235] Thus having described in detail a series of experiments as to the effects of an alteration of diet supplied to the larvæ of various _hymenoptera_, M. Fabre writes: "Tout cela est bien autrement grave que les petits riens invoqués par Darwin." (_Souvenirs entomologiques_, 3rd Series, p. 330.) [236] _Journal of Linnean Society_, vol. xix. [237] _Hibbert Journal_, January, 1903, p. 218. [238] _Revue de Philosophie_, April 1, 1904. [239] _Souvenirs entomologiques_, 3rd Series, p. 317. [240] For some further testimonies on this head see Appendix. [241] _Nature_, September 10, 1891. [242] _Coming of Age of the Origin of Species._ [243] _De opere sex dierum_, ii. 10, n. 12. [244] _Modern Idea of Evolution_, p. 97. [245] Darwin (_Origin of Species_, p. 274, 6th Edition) considers it "incredible" that the same identical species should originate twice even under the very same conditions. In the following passage, Haeckel affirms such unity of origin in respect of a most remarkable species of wide-reaching affinities. "All morphologists arrive at the firm conviction that all vertebrata, from the _Amphioxus_ upwards to man himself, all fishes, amphibia, reptiles, birds, and mammals, descend originally from a single vertebrate ancestor, for we cannot imagine that all the different and highly complicated conditions of life which, through a long series of processes or stages of development, led to the typical formation of a vertebrate, have accidentally happened together more than once in the course of the earth's history." (Address to Munich meeting of German Association, vid. _Nature_, October 4, 1877.) [246] _Origin of Species_ (6th Edition), p. 265. [247] _Les Emules de Darwin_, ii., 76. [248] _History of Plant Life and its bearings on Theory of Evolution_ (1898). [249] Harebell. [250] According to the most recent system of classification, the Monopetalæ, now re-christened _Sympetalae_, are ranked above the Polypetalæ, the family of the _Compositae_ being highest of all. [251] _Proceedings_, vol. v., p. 17, etc. (1875-6). The substance of this address appeared as an article in the _Contemporary Review_, February, 1877, entitled, "Evolution and the Vegetable Kingdom." [252] See Appendix B. p. 284. [253] _Modern Ideas of Evolution_ (6th Edition), pp. 107, seq. [254] These first mammals, which were exceedingly small, are supposed by most naturalists to have been Marsupials. They would appear presently to have become extinct, no traces of them having been found in the chalk, a formation so rich in other organic remains. As Professor Marsh tells us on this subject (_Nature_, September 27, 1877, p. 471):