[237] Über den Einfluss der Isolirung auf die Artbildung. Leipzig, 1872, p. 33.
[238] Duméril represents the teeth of the vomer as separated from those of the os palatinum by a gap. This is probably accidental, since Gegenbaur (Friedrich u. Gegenbaur, the skull of Axolotl, Würzburg, 1849) figures the rows of teeth as passing over from the one bone to the other without interruption. This was the case with the Axolotls which I have been able to examine on this point; but this small discrepancy is, however, quite immaterial to the question here under consideration.
[239] See O. Hertwig “Über das Zahnsystem der Amphibien und seine Bedeutung für die Genese des Skelets der Mundhöhle.” Archiv. für microsc. Anat., vol. xi. Supplement, 1874.
[240] [Eng. ed. These Amblystomas have since died and have been minutely described by Dr. Wiedersheim. See his memoir, “Zur Anatomie des Amblystoma Weismanni,” in Zeit. für wiss. Zool., vol. xxxii. p. 216.]
[241] See Strauch, loc. cit. p. 10.
[242] See [Part I]. of this volume.
[243] [This is the principle of “Degeneration” recognized by Darwin (see “Origin of Species,” 6th ed. p. 389, and “Descent of Man,” vol. i. p. 206), and given fuller expression to by Dr. Anton Dohrn (see his work entitled “Der Ursprung der Wirbelthiere und das Princip des Functionswechsels.” Leipzig, 1875). A large number of cases have been brought together by Prof. E. R. Lankester, in his recent interesting work on “Degeneration, a Chapter in Darwinism.” Nature series, 1880. R.M.]
[244] “Sulla Larva del Triton Alpestris.” Archivio per la Zoologia. Genova e Torino, 1861, vol. i. pp. 206–211.
[245] See also Lubbock “On the Origin and Metamorphoses of Insects,” London, 1874.
[246] See the first essay “On the Seasonal Dimorphism of Butterflies,” p. [82].